424B4

The Rubicon Project, Inc. is offering 5,416,796 shares of common stock and the selling stockholders named in this prospectus are offering 1,354,199 shares of common stock. We will not receive any proceeds from the sale of shares by the selling stockholders. This is our initial public offering and no public market currently exists for our common stock.

Our common stock has been approved for listing on the New York Stock Exchange under the symbol “RUBI.”

We are an “emerging growth company” as defined under the federal securities laws and are subject to reduced public company reporting requirements. Investing in our common stock involves risks. See “Risk Factors” beginning on page 16.

We have granted the underwriters the right to purchase up to an additional 1,015,649 shares of common stock to cover over-allotments.

The Securities and Exchange Commission and state securities regulators have not approved or disapproved these securities, or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The underwriters expect to deliver the shares of common stock to purchasers on or about April 7, 2014.

You should rely only on the information contained in this prospectus or in any free-writing prospectus we may authorize to be delivered or made available to you. We have not, and the selling stockholders and underwriters have not, authorized anyone to provide you with additional or different information. We and the selling stockholders are offering to sell, and seeking offers to buy, shares of our common stock only in jurisdictions where offers and sales are permitted. The information in this prospectus or any free-writing prospectus is accurate only as of its date, regardless of its time of delivery or of any sale of shares of our common stock. Our business, financial condition, results of operations and prospects may have changed since that date.

Until April 26, 2014 (25 days after the date of this prospectus), all dealers that buy, sell or trade shares of our common stock, whether or not participating in this offering, may be required to deliver a prospectus. This delivery requirement is in addition to the obligation of dealers to deliver a prospectus when acting as underwriters and with respect to their unsold allotments or subscriptions.

For investors outside the United States: we have not, and the selling stockholders and underwriters have not done anything that would permit this offering, or possession or distribution of this prospectus, in any jurisdiction where action for that purpose is required, other than in the United States. Persons outside the United States who come into possession of this prospectus must inform themselves about, and observe any restrictions relating to, the offering of the shares of common stock and the distribution of this prospectus outside of the United States.

PROSPECTUS SUMMARY

This summary highlights selected information contained elsewhere in this prospectus. This summary does not contain all the information that you should consider before deciding to invest in our common stock. You should read the entire prospectus carefully, including “Risk Factors,” “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and our consolidated financial statements and notes to those consolidated financial statements before making an investment decision. Some of the statements in this prospectus constitute forward-looking statements. For more information, see “Special Note Regarding Forward-Looking Statements.”

Overview

We are a technology company on a mission to automate the buying and selling of advertising. Our Advertising Automation Cloud is a highly scalable software platform that powers and optimizes a leading marketplace for the real time trading of digital advertising between buyers and sellers. Through the speed and big data analytics of our algorithm-based solution, we have transformed the cumbersome, complex process of buying and selling digital advertising into a seamless automated process that optimizes results for both buyers and sellers. Buyers of digital advertising use our platform to reach 97% of Internet users in the United States and over 600 million Internet users globally on some of the world’s leading websites and applications. Sellers of digital advertising use our platform to maximize revenue from advertising, decrease costs and protect their brands and user experience, while accessing a global market of buyers representing over 100,000 brands since our inception. The benefits we provide to both buyers and sellers, and the time and effort spent by both buyers and sellers to integrate with our platform and associated applications, give us a critical position in the digital advertising ecosystem.

Our Advertising Automation Cloud incorporates proprietary machine-learning algorithms, sophisticated data processing, high volume storage, detailed analytics capabilities, and a distributed infrastructure. We analyze billions of data points in real time to enable our solution to make approximately 300 data-driven decisions per transaction in milliseconds, and to execute up to 2.5 million peak queries per second, approximately 25 billion transactions per week and 3 trillion bid requests per month. Our Advertising Automation Cloud features applications for digital advertising sellers, including websites, applications and other digital media properties, to sell their advertising inventory; applications for buyers, including demand side platforms, or DSPs, ad networks and advertising agencies, to buy advertising inventory; and an exchange over which such transactions are executed. Together, these features power and optimize a comprehensive, transparent, independent advertising marketplace that brings buyers and sellers together and facilitates intelligent decision-making and automated transaction execution for the advertising inventory we manage on our platform. We believe we help increase the volume and effectiveness of advertising, increasing revenue for sellers and improving return on advertising investment for buyers.

We have direct relationships built on technical integration with over 700 sellers of digital advertising, including approximately 40% of the U.S. comScore 100, which is a list of the top U.S. digital sellers by reach. We believe that our direct relationships and integration with sellers, which differentiate us from many other participants in the advertising ecosystem, make us a vital participant in the digital advertising industry. Our integration of sellers into our platform gives sellers the ability to monetize a full variety and volume of inventory. At the same time, buyers leverage our platform to manage their advertising spending, simplify order management and campaign tracking, obtain actionable insights into audiences for their advertising and access impression level purchasing from hundreds of sellers. We believe buyers need our platform because of our powerful solution and our direct relationships and integration with some of the world’s largest websites and applications. Our solution is constantly self-optimizing based on our ability to analyze and learn from vast volumes of data. The additional data we obtain from the volume of transactions on our platform help make our machine-learning algorithms more intelligent, leading to higher quality matching between buyers and sellers, better return on investment for buyers

and higher revenue for sellers. As a result of that high quality matching, we attract even more sellers which in turn attracts more buyers and vice versa. We believe this self-reinforcing dynamic creates a strong platform for growth. The historical and real time data we derive from the over 700 seller integrations, 25 billion transactions per week, 3 trillion bid requests per month and 600 million Internet users globally that interact with our platform per month inform our machine-learning algorithms to create a size, scale and capability that is difficult to replicate.

We believe we are positioned to take advantage of several trends in the advertising industry, including the shift in advertising spending from analog to digital advertising, the move towards automation and the convergence of media across multiple channels. The display, mobile and video digital advertising market is projected to grow to $90 billion by 2017, and the need for automation in this market is growing commensurately, with real time bidding alone projected to grow at a compounded annual growth rate of 57% from $1.4 billion in 2011 to $20.8 billion in 2017.

In 2013, our revenue was $83.8 million, a 47% increase over 2012, and we recorded a net loss of $9.2 million and Adjusted EBITDA of $11.2 million. In 2012, our revenue was $57.1 million, a 54% increase over 2011, and we recorded a net loss of $2.4 million and Adjusted EBITDA of $9.2 million. In 2011, our revenue was $37.1 million, and we recorded a net loss of $15.4 million and negative Adjusted EBITDA of $6.7 million. For information on Adjusted EBITDA, and a reconciliation of Adjusted EBITDA to net loss on the basis of accounting principles generally accepted in the United States, or GAAP, please refer to “Summary Consolidated Financial and Other Data.”

Advertising spending transacted on our platform has grown significantly. Managed revenue is an operational measure that represents this advertising spending. Managed revenue would represent our revenue if we were to record our revenue on a gross basis instead of a net basis. Managed revenue does not represent revenue reported on a GAAP basis. We review managed revenue for internal management purposes to assess market share and scale and to compare our performance to others in our industry that report revenue on a gross basis. In 2013, our managed revenue was $485.1 million, which represents a 43% increase over managed revenue of $338.9 million in 2012. Our managed revenue of $338.9 million in 2012 represents a 42% percent increase over managed revenue of $238.8 million in 2011.

Our Industry

Shift Towards Digital Advertising. In response to consumers spending more time consuming digitally delivered content over the Internet, mobile networks and digital television, the advertising industry is in the midst of a decades-long shift from advertising in analog and print media, like print newspapers, magazines, broadcast radio and television, to digital advertising. As a result of the vast amount of audience data available, digital advertising has the potential to drive return on advertising investment for advertisers many times higher than print, broadcast radio and television. Technological advances are also enabling sellers to optimize and expand the monetization of their inventory.

Development of a Complex Digital Advertising Ecosystem Comprising a Large Number of Buyers, Sellers and Other Participants. Advertisers and sellers of advertising inventory have come to rely on a complex ecosystem made up of multiple technology and service providers, as described below.

Buyers: At one end of the ecosystem, spending begins with advertisers, who often engage advertising agencies to help plan and execute their digital advertising campaigns.

Buyers include agencies as well as advertiser aggregators through which agencies traditionally execute their digital advertising campaigns, including DSPs, ad networks and agency trading desks, or ATDs.

Sellers: At the other end of the ecosystem, sellers create websites and applications that contain viewable space for advertisements, or impressions, that can be delivered to users as they visit and navigate through websites and applications. These impressions can be sold to buyers either in advance via manual or automated direct sales efforts, or in real time on an impression-by-impression basis via a third-party through the digital advertising ecosystem.

Other Sell-Side Participants: Sellers may use additional sell-side representatives to connect with buyers, such as supply side platforms, or SSPs, and ad servers.

Exchanges: Buyers and sellers may sometimes come together through an exchange that matches and presents available impressions to buyers.

Costs, Inefficiencies and Lack of Transparency Inherent in Existing Ecosystem. This ecosystem of various buyers, sellers and other intermediaries has helped advertisers access digital media, but it is inefficient and has fallen short of truly enabling them to take advantage of the full potential of digital advertising. We believe, based on industry research, that only approximately $0.40 of every dollar spent by an advertiser is ultimately realized by the seller.

Complicated and Manual Workflow for Buying and Selling Digital Advertising. Despite significant technological advances with respect to delivery of digital advertising, the process of planning and executing a digital advertising campaign remains cumbersome and highly manual. These manual and complicated workflows lead to inefficiencies, wasted dollars for sellers and lost opportunities for advertisers to reach users. According to NextMark, it can cost an advertiser up to $40,000 and 480 man-hours to plan and execute a $500,000 advertising campaign.

Digital Advertising is Complex and Challenging to Automate

Due to the size and complexity of the advertising ecosystem and purchasing process, manual processes can no longer effectively optimize or manage digital advertising. This has created a need to automate the digital advertising industry and to simplify the process of buying and selling advertising. However, a number of factors make digital advertising complex and challenging to automate:

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Perishable Inventory. The inventory of available impressions is highly perishable due to the fact that each impression must be valued, auctioned, successfully purchased, and then the winning bidder must be notified and must serve the advertisement, all in the split second between the time a user types in a web-address or is redirected to a website or application and the time the page is loaded.

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Complex Impression Level Matching. In order for buyers to maximize their ability to target specific audiences and for sellers to optimize their revenue, there is a need for a technology solution that can match buyer and seller objectives at a large scale to optimize the delivery of advertising on an impression-by-impression basis.

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Large Multi-Variate Datasets. The volume of data available to optimize digital advertising is enormous, and buyers and sellers need a solution capable of analyzing, processing and interpreting these large amounts of data and executing buy and sell orders informed by such data, all in real time.

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Fragmented Buyer and Seller Base. The enormous variety of buyers and sellers in the digital advertising industry has created a need for a solution that is capable of seamlessly connecting a highly fragmented global buyer and seller base.

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Brand Security and User Experience Concerns. Both buyers and sellers need a solution that is capable of following specified rules established by buyers and sellers to maintain brand integrity and deliver relevant advertisements that create a positive user experience, while efficiently executing a large volume of transactions.

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Large and Highly Unpredictable Traffic Volumes. Sellers need a platform that can effectively respond to and monetize inventory during unpredictable spikes in user volumes.

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Lack of Standardized Ad Formats and Data. An available advertising impression can vary based on a variety of factors, and buyers and sellers require a platform that can on a real time basis match the large assortment of available advertising impressions with potential buyers.

Rubicon Project: Our Advertising Automation Cloud Enables the Digital Advertising Marketplace

Rubicon Project was founded to address the challenges associated with the digital advertising ecosystem and to enable a marketplace where buyers and sellers of advertising can readily buy and sell advertising on an automated basis. Our Advertising Automation Cloud optimizes the sale and purchase of advertising across a full spectrum of inventory for all types of buyers and sellers and across all devices. We believe there are few market participants that are directly integrated with sellers in a way that allows sellers to make a wide range and volume of advertising inventory readily available in the marketplace. Our solution enables buyers and sellers to transact through our comprehensive automation offerings including real time bidding, or RTB, static bidding and direct orders. Our solution integrates RTB, static bidding and direct order offerings into a unified auction across all types of buyers, while matching available impressions with advertisements based upon various criteria. Our solution can complete the many steps and analyses required to execute a typical digital advertising transaction within an average of approximately 80 milliseconds.

Big Data Analytics and Machine-Learning Algorithms. We have developed proprietary machine-learning algorithms that analyze billions of data points from our massive data repositories to enable our solution to make approximately 300 real time data-driven decisions per transaction and to execute approximately 3 trillion bid requests per month.

Dual Network Effects Drive an Efficient and Self-Optimizing Marketplace. Our solution is constantly self-optimizing based on our ability to analyze and learn from vast volumes of data. The additional data we obtain from the volume of transactions on our platform helps make our machine-learning algorithms more intelligent, leading to higher quality matching between buyers and sellers, better return on investment for buyers and higher revenue for sellers. As a result of that high quality matching, we attract even more sellers, which in turn attracts more buyers, and vice versa. We believe this self-reinforcing dynamic creates a strong platform for growth.

Critical Position in Digital Advertising Ecosystem. In order to maximize the monetization of the full range and volume of their advertising inventory through our platform, gain actionable insights from the data we have amassed and consolidate and compile payments and billing, sellers integrate into our platform in a way that we believe would cause them to experience high switching costs to move large volumes of their inventory to a new platform. At the same time, we believe that buyers need our platform to benefit from our powerful solution and our direct relationships and integration with some of the world’s largest websites and applications. The benefits we provide to both buyers and sellers, and the time and effort spent by both buyers and sellers to integrate with our applications, give Rubicon Project a critical position in the digital advertising ecosystem.

Platform Applications

To enhance the value our Advertising Automation Cloud brings to the marketplace, we offer a growing set of applications to address the critical needs of buyers and sellers:

Applications for Sellers. We have direct relationships and integration with the sellers on our platform and provide applications to help them increase their digital advertising revenue, reduce costs, protect their brands and user experience, and reach more buyers efficiently. Sellers realize the following benefits from our platform:

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Maximized revenue for a broad range of digital advertising inventory without volume or geographic constraints.

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Automated sales with leading buyers via RTB, static bidding and direct orders.

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Integrated solution for digital advertising needs.

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Significantly streamlined sales, operations and finance workflow.

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Brand security.

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Enhanced user experience through delivery of relevant advertisements.

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Advanced reporting and analytics and actionable insights.

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Consolidated payments and transparent tracking and billing system.

Applications for Buyers. Buyers leverage our applications to access a large audience and to purchase advertising inventory based on their key demographic, economic, and timing criteria, allowing them to streamline their purchasing operations, increase the efficiency of their spending and the effectiveness of their advertising campaigns. Buyers realize the following benefits from our platform:

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Direct access to a global audience and hundreds of premium sellers.

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Ability to purchase via RTB, static bidding or direct orders.

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Ability to integrate existing buying technologies or buy directly through us.

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Optimized return on investment by consolidating spending on one platform.

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Simplified order management and campaign tracking.

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Transparency and control over advertising spending.

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Brand security.

Our Market Opportunity

We believe that important trends greatly enhance our market opportunity, namely: the shift in advertising spending to digital advertising, the move towards automation and the convergence of media across multiple channels.

Rapid Growth in Digital Advertising Spending. As media consumption shifts to digital delivery via the Internet, digital television and mobile devices, digital advertising spending is growing at a significantly faster rate than advertising spending on analog and print media. We believe that there will be continued expansion of digital advertising as advertising spending “catches up” to time spent on the Internet and mobile devices. According to the PwC Entertainment and Media Global Outlook: 2013-2017, published in June 2013, display, mobile and video digital advertising are forecasted to grow from approximately $43 billion in 2012 to $90 billion in 2017, a 16% compounded annual growth rate, and our calculations based on data from eMarketer indicate that the current opportunity for monetizing online media consumption is over $32 billion annually in the United States.

Increasing Demand for Automation and Real Time Purchase and Sale of Advertising. As digital advertising has grown in complexity, the need for automation has increased commensurately. According to International Data Corporation, or IDC (October 2013), global RTB spending by advertisers is expected to grow from $1.4 billion in 2011 to $20.8 billion in 2017, a compounded annual growth rate of 57%. RTB is just one aspect of advertising automation, and static bidding and direct orders can also benefit significantly from automation.

Trend Towards Automation of Analog and Print Advertising Markets. Over time, we also expect analog and print advertising markets to automate, and we view our long-term mission, and opportunity, as the

automation of all buying and selling of advertising. As more content is being delivered digitally, and with the continued shift of consumption patterns to Internet and mobile devices, television and Internet content are beginning to converge, blurring the historical distinctions between analog and print media and digital media, and requiring advertisers to consider their advertising strategies over multiple media. We believe these trends give us the opportunity to automate a portion of the larger advertising market.

Competitive Strengths

We believe the following key strengths differentiate us from our competitors and strategically position us within the digital advertising marketplace:

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Technology Platform with Differentiated Scalability and Real Time Processing Speed. Our specially engineered hardware, our software infrastructure technology and our database enable us to process many complex calculations per transaction in milliseconds. The speed and scale of our platform provide buyers and sellers with increased market liquidity and access, optimal pricing and reduced latency, limited loss of perishable inventory, better matching and increased efficacy of advertisements.

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Highly Evolved Machine-Learning Algorithms that Leverage Big Data. Utilizing our highly sophisticated algorithms, we are able to optimize sellers’ monetization of their inventory and to offer more sophisticated targeting options to buyers that allow them to maximize the impact of their advertising spend.

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Dual Network Effects. As we process more volume on our automated platform, we accumulate more data, such as pricing, geographic and preference information, data on how best to optimize yield for sellers and more. This additional data helps make our machine-learning algorithms more intelligent and this leads to more effective matching between buyers and sellers. As a result, more buyers and sellers are attracted to our platform, from which we get more data, which further reinforces the network effect and thereby increases market liquidity, which benefits both buyers and sellers.

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Direct Relationships and Integration with High Quality Sellers. Our Advertising Automation Cloud builds on our direct relationships and integration with our seller base. We believe that these direct relationships make us a critical participant in the digital advertising ecosystem, and make our solution one that would be difficult and time consuming for sellers to replicate, resulting in low seller attrition.

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Leading User Reach and Significant Scale. According to comScore (February 2014), we reach 97% of Internet users in the United States, which establishes us as a leader in digital advertising. Our reach of over 600 million Internet users globally enables us to provide buyers with the ability to execute their largest campaigns and easily reach their target audiences.

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Comprehensive Solution Covering All Types of Inventory and Demand. We enable sellers to offer a full range and volume of their advertising inventory through several types of transactions, including RTB, static bidding and direct orders. The availability of this wide range and volume of inventory, together with the multiple ways of purchasing, attracts a similarly wide variety of buyers, giving us access to a wider digital advertising market.

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Scalable Business Model. As we bring buyers and sellers onto our platform, they transact in an automated fashion without additional sales and marketing efforts from us, allowing us to grow the managed revenue on our platform without a proportional increase in our sales and marketing expenses.

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Brand Security. We believe that the rules that we establish on our platform, together with the scalability and speed of our platform, allow us to uniquely incorporate brand security for both buyers and sellers in a manner that allows them to buy and sell inventory safely despite the challenges presented by the volume of content and dynamic nature of digital advertising.

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Independence. We believe our independent market position enables us to better serve buyers and sellers because we are not burdened with any structural conflicts arising from owning and operating digital media properties while offering advertising purchasing solutions to buyers.

Growth Strategies

Our goal is to be the leading marketplace for digital advertising and ultimately drive automation throughout the advertising industry. The core elements of that growth strategy include:

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Growing our business with existing buyers and attracting new buyers to our platform.

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Increasing penetration of existing sellers and attracting new sellers.

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Enhancing our leadership position by investing in innovation and expansion.

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Accelerating our global expansion and entering new markets.

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Bringing automation to additional media.

Risks Affecting Us

Investing in our common stock involves significant risks. You should carefully consider the risks described in “Risk Factors” before making a decision to invest in our common stock. The occurrence of any of these risks could have a material adverse effect upon our business, financial condition or results of operations. In such case, the trading price of our common stock would likely decline, and you may lose part or all of your investment. Below is a summary of some of the principal risks we face.

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We must grow rapidly to remain a market leader and to accomplish our strategic objectives. If we fail to grow, or fail to manage our growth effectively, our value may decline.

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In order to meet our growth objectives, we will need to rely upon our ability to innovate, the continued adoption of our solution by buyers and sellers, the extension of the reach of our solution into evolving digital media and growth in new geographic markets.

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Our technology development effort may be inefficient or ineffective, which may harm our ability to attract and retain buyers and sellers.

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We must scale our technology infrastructure to support our growth and transaction volumes. If we fail to do so, we may lose buyers, sellers and revenue from transactions.

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Our limited operating history makes it difficult to evaluate our business and prospects and may increase the risks associated with your investment; we have a history of losses and may not achieve and sustain profitability in the future.

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The digital advertising market is relatively new and dependent on growth in various digital advertising channels, and has been highly volatile in the past. If this market develops more slowly or differently than we expect, our business, growth prospects and financial condition would be adversely affected.

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We operate in an intensely competitive market that includes companies that have greater financial, technical and marketing resources than we do.

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Our business depends on our ability to collect and use data to deliver advertisements, and to disclose data relating to the performance of our ads, and any limitation on the collection, use or disclosure of this data, such as limitations on the use of “cookies,” could significantly diminish the value of our services and cause us to lose sellers, buyers and revenue.

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We depend on owners of digital media properties for advertising inventory to deliver advertising campaigns, and any decline in the supply of advertising inventory from these sellers could hurt our business.

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Our contracts with buyers are generally not exclusive and generally do not require minimum volumes or long-term commitments. If a buyer, or group of buyers, representing a significant portion of our business decides to materially reduce the use of our solution, we could experience an immediate and significant decline in our revenue and profitability, which would harm our business.

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Our directors, executive officers, and each of our stockholders who own greater than 5% of our outstanding common stock, in the aggregate, will beneficially own approximately 57.2% of the outstanding shares of our common stock after this offering, based on the number of shares outstanding as of March 18, 2014. As a result, these stockholders will continue to have substantial control over us after this offering and will be able to influence or control matters requiring approval by our stockholders, including the election of directors and the approval of mergers, acquisitions or other extraordinary transactions.

Corporate Information

We were incorporated in 2007 in Delaware. Our principal executive offices are located at 12181 Bluff Creek Drive, 4^th Floor, Los Angeles, CA 90094. Our telephone number is (310) 207-0272. Our website is www.rubiconproject.com. The information on, or that can be accessed through, our website is not part of this prospectus.

Reverse Stock Split

Our board of directors and stockholders approved a 1-for-2 reverse split of our common stock and a proportional adjustment to the conversion ratio of our Series A, Series B, Series C and Series D convertible preferred stock, or preferred stock, which was effected on March 18, 2014. All references to common stock, options to purchase common stock, restricted stock, share data, per share data, warrants and related information have been retroactively adjusted where applicable in this prospectus to reflect the reverse stock split of our common stock as if it had occurred at the beginning of the earliest period presented.

THE OFFERING


Common stock offered by us		5,416,796 shares

Common stock offered by the selling stockholders		1,354,199 shares

Total common stock offered		6,770,995 shares

Over-allotment option		1,015,649 shares (with all shares being offered by us)

Common stock to be outstanding after this offering		34,715,103 shares (35,730,752 shares if the underwriters exercise their option to purchase additional shares from us in full)

Use of proceeds		We expect to receive net proceeds from this offering of approximately $72.2 million, after deducting the underwriting discount and commissions and estimated offering expenses payable by us. We intend to use the net proceeds from this offering for general corporate purposes, including working capital, sales and marketing activities, engineering initiatives including enhancement of our solution and investment in technology and development, general and administrative expenses and capital expenditures. We also may use a portion of the net proceeds from this offering to acquire or invest in technologies, solutions or businesses that complement our business, although we have no present commitments to complete any such transactions. See “Use of Proceeds.”

New York Stock Exchange symbol		“RUBI”

The number of shares of our common stock to be outstanding after this offering is based on 26,551,195 shares of our common stock outstanding as of December 31, 2013, and excludes:

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7,584,284 shares of common stock issuable upon exercise of stock options outstanding at December 31, 2013 that remain outstanding as of March 18, 2014, consisting of (i) 8,359,589 shares of common stock issuable upon the exercise of stock options outstanding as of December 31, 2013 with a weighted average exercise price of $6.13 per share, less (ii) a reduction as of March 18, 2014 of 775,305 in the number of shares issuable upon exercise of stock options that were outstanding as of December 31, 2013 as a result of option exercises, forfeitures and cancellations, which will effectively be extinguished as of the date of the offering;

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12,587 shares of common stock issuable upon exercise of an outstanding warrant with an exercise price of $3.11 per share as of December 31, 2013 and as of March 18, 2014;

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546,741 shares of common stock issued upon exercise of outstanding stock options between January 1, 2014 and March 18, 2014;

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500,000 shares of common stock issuable upon the exercise of new stock options granted between January 1, 2014 and March 18, 2014 with a weighted average exercise price of $16.22 per share;

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2,200,371 shares of restricted stock issued between January 1, 2014 and March 18, 2014;

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2,100,000 shares of our common stock reserved for future issuance under our 2014 Equity Incentive Plan, which takes effect upon consummation of this offering; and

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525,000 shares of our common stock reserved for issuance under our 2014 Employee Stock Purchase Plan, which also takes effect as of the consummation of this offering.

Our 2014 Equity Incentive Plan and our 2014 Employee Stock Purchase Plan also provide for automatic annual increases in the number of shares reserved thereunder as more fully described in “Executive Compensation – Employee Benefit Plans.”

Except as otherwise indicated, all information in this prospectus assumes:

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a 1-for-2 reverse split of our common stock and a proportional adjustment to the conversion ratio of our preferred stock that was effected on March 18, 2014;

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the effectiveness of our amended and restated certificate of incorporation and the adoption of our amended and restated bylaws in connection with the completion of this offering;

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the automatic conversion of each outstanding share of our convertible preferred stock into one-half of a share of our Class A common stock upon completion of this offering;

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the automatic conversion of each outstanding share of our Class B common stock into one share of our Class A common stock immediately prior to the completion of this offering;

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the conversion of our Class A common stock (including all shares of Class A common stock issued upon conversion of our convertible preferred stock and Class B common stock as described above) into a single class of common stock upon completion of this offering;

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the automatic conversion of an outstanding warrant exercisable for 25,174 shares of our convertible preferred stock into a warrant exercisable for 12,587 shares of common stock upon the completion of this offering;

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the net exercise in connection with this offering of an outstanding warrant for 845,867 shares of our convertible preferred stock, resulting in the issuance of 286,055 shares of common stock upon such net exercise based on the initial public offering price of $15.00 per share and after giving effect to surrender of shares to pay the exercise price and the conversion of the net number of shares of our convertible preferred stock to common stock (reflecting the 1-for-2 reverse stock split);

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no exercise of outstanding options and warrants (other than as described above) subsequent to December 31, 2013; and

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no exercise by the underwriters of their option to purchase additional shares from us.

SUMMARY CONSOLIDATED FINANCIAL AND OTHER DATA

The following table sets forth a summary of our consolidated historical financial and operating data for the periods indicated. The consolidated statements of operations data for the years ended December 31, 2011, 2012 and 2013, and the consolidated balance sheet data as of December 31, 2012 and 2013 have been derived from our audited consolidated financial statements included elsewhere in this prospectus.

The historical results presented below are not necessarily indicative of the results to be expected in the future. This information should be read in conjunction with “Risk Factors,” “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” and the consolidated financial statements and related notes included elsewhere in this prospectus.


	Year Ended December 31,
	2011			2012			2013
	(in thousands, except per share data)
Revenue	$	37,059		$	57,072		$	83,830
Expenses:
Costs of revenue⁽¹⁾		12,893			12,367			15,358
Sales and marketing⁽¹⁾		17,748			20,458			25,811
Technology and development⁽¹⁾		12,496			13,115			18,615
General and administrative⁽¹⁾		8,926			12,331			27,926

Total expenses		52,063			58,271			87,710

Loss from operations		(15,004	)		(1,199	)		(3,880	)
Other expense, net		269			1,029			5,122

Loss before income taxes		(15,273	)		(2,228	)		(9,002	)
Provision for income taxes		136			134			247

Net loss	$	(15,409	)	$	(2,362	)	$	(9,249	)
Cumulative preferred stock dividends⁽²⁾		(4,244	)		(4,255	)		(4,244	)

Net loss attributable to common stockholders	$	(19,653	)	$	(6,617	)	$	(13,493	)

Basic and diluted net loss per share attributable to common stockholders⁽³⁾⁽⁴⁾	$	(1.95	)	$	(0.60	)	$	(1.17	)

Basic and diluted weighted-average shares used to compute net loss per share attributable to common stockholders⁽⁴⁾		10,099			11,096			11,488

Pro forma net loss per share—basic and diluted⁽³⁾⁽⁴⁾							$	(0.20	)

Pro forma weighted-average common shares outstanding—basic and diluted⁽⁴⁾								25,898

(1)	Stock-based compensation expense included in our expenses was as follows:


	Year Ended December 31,
	2011		2012		2013
	(in thousands)
Cost of revenue	$	270	$	78	$	87
Sales and marketing		309		1,039		1,105
Technology and development		858		828		1,645
General and administrative		831		1,099		3,515

Total	$	2,268	$	3,044	$	6,352

(2)

The holders of the convertible preferred stock are entitled to cumulative dividends prior and in preference to common stock. Because the holders of our convertible preferred stock are entitled to participate in dividends, net loss attributable to common stockholders is equal to net loss adjusted for cumulative preferred stock dividends for the period. Immediately upon the closing of this offering, each outstanding share of convertible preferred stock will be automatically converted into one-half of a share of our common stock and these holders will not be entitled to the cumulative dividends. See Note 11 to our consolidated financial statements for a description of our convertible preferred stock.

(3)	See Note 2 to our consolidated financial statements for a description of the method used to compute basic and diluted net loss per share attributable to common stockholders and pro forma basic and diluted net loss per share attributable to common stockholders.

(4)	All share, per-share and related information have been retroactively adjusted, where applicable, to reflect the impact of a 1-for-2 reverse stock split, including an adjustment to the preferred stock conversion ratio, which was effected on March 18, 2014.

Consolidated Balance Sheet Data


	At December 31
	2012			2013
	(in thousands)
Cash and cash equivalents	$	21,616		$	29,956
Accounts receivable, net	$	67,335		$	94,722
Property, equipment and capitalized software, net	$	12,697		$	15,916
Total assets	$	108,014		$	149,887
Debt and capital lease obligations, current and non-current	$	5,215		$	4,181
Total liabilities	$	90,005		$	133,727
Convertible preferred stock	$	52,571		$	52,571
Common stockholders’ deficit	$	(34,562	)	$	(36,411	)

Operational and Financial Measures


	Year Ended
	December 31, 2011			December 31, 2012			December 31, 2013

Operational Measures:
Managed revenue (in thousands)	$	238,838		$	338,918		$	485,080
Paid impressions (in billions)		980			1,431			1,336
Average CPM	$	0.24		$	0.24		$	0.36
Take rate		15.5	%		16.8	%		17.3	%
Financial Measures:
Revenue (in thousands)	$	37,059		$	57,072		$	83,830
Adjusted EBITDA (in thousands)	$	(6,698	)	$	9,205		$	11,223

Managed Revenue

internal management purposes to assess market share and scale. Many companies in our industry record revenue on a gross basis, so tracking our managed revenue allows us to compare our results to the results of those companies.

Our managed revenue is influenced by the volume and characteristics of advertising inventory transacted on our platform, or paid impressions, and pricing, expressed as cost per thousand impressions or “average CPM.”

Paid Impressions

We define a paid impression as an impression sold to an advertiser and subsequently displayed on a website or mobile application, which is transacted via our platform through either direct or indirect relationships between us and buyers and sellers or between buyers and sellers directly. We use paid impressions as one measure to assess the performance of our platform, including the effectiveness and efficiency at which buyers and sellers are trading via our platform and using our solution, and to assist us in tracking our revenue generating performance and operational efficiencies. The number of paid impressions may fluctuate based on various factors, including the number and spend of buyers using our solution, the number of sellers, their allocation of advertising inventory using our solution, our traffic control initiatives and the seasonality in our business. Because of the volatility of this metric, we believe that paid impressions are useful to review on an annual basis.

Average CPM

Pricing is generally expressed as average cost per thousand impressions, or “average CPM.” Average CPM is an operational measure that represents the average price at which paid impressions are sold. We review average CPM for internal management purposes to assess buyer spend, liquidity in the marketplace, inventory quality and integrity of our algorithms. Average CPM may be influenced by our inventory placements and demand for such inventory facilitated by our relationships with both buyers and sellers, as well as by a variety of other factors, including the precision of matching of an advertisement to an audience, changes in our algorithms, seasonality, quality of inventory provided by sellers, penetration of various channels and advertising units and changes in buyer spend levels. We expect average CPM to increase with the continued adoption of our solution by premium buyers and sellers, resulting in a higher quantity of premium advertising inventory available to advertisers. Because of the volatility of this metric, we believe that average CPM is useful to review on an annual basis. We compute average CPM by dividing managed revenue by total paid impressions and multiplying by 1,000.

Take Rate

Take rate is an operational measure that represents our share of managed revenue. We review take rate for internal management purposes to assess the development of our marketplace with buyers and sellers. Our take rate can be affected by a variety of factors, including the terms of our arrangements with buyers and sellers active on our platform in a particular period, the scale of a buyer or seller’s activity on our platform, the implementation of new products, platforms and solution features, and the overall development of the digital advertising ecosystem.

Adjusted EBITDA

income, operating income or any other measure of financial performance calculated and presented in accordance with GAAP. Adjusted EBITDA eliminates the impact of items that we do not consider indicative of our core operating performance. You are encouraged to evaluate these adjustments and the reason we consider them appropriate. We believe Adjusted EBITDA is useful to investors in evaluating our operating performance for the following reasons:

•

Adjusted EBITDA is widely used by investors and securities analysts to measure a company’s operating performance without regard to items such as stock-based compensation expense, depreciation and amortization, interest (income) expense, net, change in fair value of preferred stock warrant liabilities, foreign exchange gains and losses, net, certain other non-recurring income or expenses such as acquisition and related costs, and provision for income taxes that can vary substantially from company to company depending upon their financing, capital structures and the method by which assets were acquired;

•

Our management uses Adjusted EBITDA in conjunction with GAAP financial measures for planning purposes, including the preparation of our annual operating budget, as a measure of operating performance and the effectiveness of our business strategies and in communications with our board of directors concerning our financial performance;

•

Adjusted EBITDA is sometimes used by the compensation committee of our board of directors in connection with the determination of compensation for our executive officers; and

•

Adjusted EBITDA provides consistency and comparability with our past financial performance, facilitates period-to-period comparisons of operations and also facilitates comparisons with other peer companies, many of which use similar non-GAAP financial measures to supplement their GAAP results.

Although Adjusted EBITDA is frequently used by investors and securities analysts in their evaluations of companies, Adjusted EBITDA has limitations as an analytical tool, and you should not consider it in isolation or as a substitute for analysis of our results of operations as reported under GAAP. These limitations include:

•

Depreciation and amortization are non-cash charges, and the assets being depreciated or amortized will often have to be replaced in the future; Adjusted EBITDA does not reflect any cash requirements for these replacements;

•

Adjusted EBITDA does not reflect changes in, or cash requirements for, our working capital needs or contractual commitments;

•

Adjusted EBITDA does not reflect cash requirements for income taxes and the cash impact of other income or expense; and

•

Other companies may calculate Adjusted EBITDA differently than we do, limiting its usefulness as a comparative measure.

The following table presents a reconciliation of net loss, the most comparable GAAP measure, to Adjusted EBITDA for each of the years indicated:


	Year Ended
	December 31, 2011			December 31, 2012			December 31, 2013
	(in thousands)
Financial Measure:
Net loss	$	(15,409	)	$	(2,362	)	$	(9,249	)
Add back (deduct):
Depreciation and amortization expense		5,538			6,857			8,438
Stock-based compensation expense		2,268			3,044			6,352
Acquisition and related items		500			503			313
Interest (income) expense, net		252			343			273
Change in fair value of preferred stock warrant liabilities		304			515			4,121
Foreign currency (gain) loss, net		216			171			728
Other income		(503	)		—			—
Provision for income taxes		136			134			247

Adjusted EBITDA	$	(6,698	)	$	9,205		$	11,223

Investing in our common stock involves a high degree of risk. These risks include, but are not limited to, those described below, each of which may be relevant to decisions regarding an investment in or ownership of our stock. You should carefully consider the risks described below, together with all of the other information in this prospectus, including our consolidated financial statements and related notes, before investing in our common stock. The realization of any of these risks could have a significant adverse effect on our reputation, business, financial condition, results of operations, growth, and ability to accomplish our strategic objectives. In that event, the price of our common stock could decline, and you could lose part or all of your investment.

We must grow rapidly to remain a market leader and to accomplish our strategic objectives. If we fail to grow, or fail to manage our growth effectively, the value of our company may decline.

The advertising technology market is dynamic, and our success depends upon the continued adoption of advertising automation and our ability to develop innovative new technologies and solutions for the evolving needs of sellers of advertising, including websites, applications and other digital media property owners, and buyers of advertising. We also need to grow significantly to develop the market reach and scale necessary to compete effectively with large competitors. This growth depends to a significant degree upon the quality of our strategic vision and planning. The advertising market is evolving rapidly, and if we make strategic errors, there is a significant risk that we will lose our competitive position and be unable to recover and achieve our objectives. Our ability to grow requires access to, and prudent deployment of, capital for hiring, expansion of physical infrastructure to run our solution, acquisition of companies or technologies, and development and integration of supporting sales, marketing, finance, administrative, and managerial infrastructure. Further, the rapid growth we are pursuing will itself strain the organization and our ability to continue that growth and to maintain the quality of our operations. If we are not able to innovate and grow successfully, the value of the company may be adversely affected.

In order to meet our growth objectives, we will need to rely upon our ability to innovate, the continued adoption of our solution by buyers and sellers for higher value advertising inventory, the extension of the reach of our solution into evolving digital media, and growth into new geographic markets.

Historically, lower value display advertising has been the largest portion of the business transacted through our solution. Our growth plans depend upon our ability to innovate, attract buyers and sellers to our solution for purposes of buying and selling higher value inventory, expand the use of our solution by buyers and sellers utilizing other digital media platforms, including mobile and video, further increase our business in new international markets, and effectively drive the increasing automation in the advertising industry. In order to innovate successfully, we must hire, train, motivate and retain talented engineers in a competitive recruiting environment, and we must deploy them based on the development priorities we establish in light of our view of the future of our industry. In mobile, video, and other emerging digital platforms, there are competitors with a significant head start in terms of technology and buyer or seller relationships. Our business model may not translate well into higher-value advertising due to market resistance or other factors, and we may not be able to innovate successfully enough to compete effectively on new platforms, or to adapt our solution and infrastructure to international markets.

Our technology development efforts may be inefficient or ineffective, which may harm our ability to attract buyers and sellers.

Our future success will depend in part upon our ability to enhance our existing solution and to develop and introduce competing new solutions in a timely manner with features and pricing that meet changing client and market requirements. We schedule and prioritize these development efforts according to a variety of factors, including our perceptions of market trends, client requirements, and resource availability. We face intense

competition in the marketplace and are confronted by rapidly changing technology, evolving industry standards and consumer needs and the frequent introduction of new solutions by our competitors that we must adapt and respond to. Our solution is complex and requires a significant investment of time and resources to develop, test, introduce into use, and enhance. These activities can take longer than we expect. We may encounter unanticipated difficulties that require us to re-direct or scale-back our efforts and we may need to modify our plans in response to changes in buyer and seller requirements, market demands, resource availability, regulatory requirements, or other factors. If development of our solution becomes significantly more expensive due to changes in regulatory requirements or industry practices, or other factors, we may find ourselves at a disadvantage to larger competitors with more resources to devote to development. These factors place significant demands upon our engineering organization, require complex planning and decision making, and can result in acceleration of some initiatives and delay of others. If we do not manage our development efforts efficiently and effectively, we may fail to produce, or timely produce, solutions that respond appropriately to the needs of buyers and sellers, and competitors may develop offerings that more successfully anticipate market evolution and address market expectations. If our solution is not responsive and competitive, buyers and sellers can be expected to shift their business to competing solutions.

We must scale our technology infrastructure to support our growth and transaction volumes. If we fail to do so, we may lose buyers, sellers and revenue from transactions.

When a user visits a website or uses an application where our technology is integrated, our technology must process a transaction for that seller and conduct an auction, often among hundreds of buyers and tens of thousands of advertiser brands, within milliseconds. Our technology must scale to process all of the advertising impressions from the collection of all of the visitors of all of the websites and applications offered on our platform combined. Additionally, for each individual advertising impression, our technology must be able to send bid requests to all of the appropriate and available buyers on our platform. It must perform these transactions end-to-end at speeds often faster than the page or application loads for the user. In short, our technology needs to processes the combined volume of every website and application and all of the buyers’ bidding technologies, which evolve over time, at speeds that are often faster than their capabilities. We must be able to continue to increase the capacity of our platform in order to support substantial increases in the number of buyers and sellers, to support an increasing variety of advertising formats and to maintain a stable service infrastructure and reliable service delivery, all to support the network effect of our solution. If we are unable to effectively increase the scale of our platform to support and manage a substantial increase in the number of transactions, as well as a substantial increase in the amount of data we process, on a cost effective basis, while also maintaining a high level of performance, the quality of our services could decline and our reputation and business could be seriously harmed. In addition, if we are not able to continue processing these transactions at fast enough speeds or if we are unable to support emerging advertising formats or services preferred by advertisers, we may be unable to obtain new buyers or sellers, we may lose existing buyers or sellers or we could lose revenue from failure to process transactions in a timely manner, any of which could cause our revenue to decline. We expect to continue to invest in our platform in order to meet increasing demand. Such investment may negatively affect our profitability and results of operations.

We have a history of losses and may not achieve and sustain profitability in the future.

We incurred net losses of $15.4 million, $2.4 million and $9.2 million, during the years ended December 31, 2011, 2012 and 2013, respectively. As of December 31, 2013, we had an accumulated deficit of $62.0 million. We may not be able to sustain the revenue growth we have experienced in recent periods, and revenue may decrease due to competitive pressures, maturation of our business or other factors. Our expenses have increased with our revenue growth, primarily due to substantial investments in our business during 2012 and 2013. You should not consider our historical revenue growth as indicative of our future performance. We expect our expenses to continue to increase substantially in the foreseeable future as we continue to expand our business, including by hiring engineering, sales, marketing and related support employees in existing and new territories, investing in our technology and developing additional digital media platforms, such as mobile and video.

Accordingly, we may not be able to achieve or sustain profitability in the future. If our revenue growth declines or our expenses exceed expectations, our financial performance will be adversely affected.

Our limited operating history makes it difficult to evaluate our business and prospects and may increase the risks associated with your investment.

We were incorporated in 2007 and consequently have only a limited operating history upon which our business and future prospects may be evaluated. We may not be able to sustain the rate of growth we have achieved to date, or even maintain our current revenue levels. We have encountered and will continue to encounter risks and difficulties frequently experienced by growing companies in rapidly evolving industries, including challenges related to recruiting; allocating and making effective use of our limited resources; achieving market acceptance of our existing and future solutions; competing against companies with greater financial and technical resources; integrating, motivating, and retaining qualified employees; developing relationships with buyers and sellers; developing new solutions; and establishing and maintaining our corporate infrastructure, including internal controls relating to our financial and information technology systems. We must improve our current operational infrastructure and technology to support significant growth and to respond to the evolution of our market and competitors’ developments. Our business prospects depend in large part on our ability to:

There is no assurance that we will meet these and other challenges, and failure to meet one or more of these objectives or otherwise adequately address the risks and difficulties that we face will have an adverse effect on our business and may result in revenue loss and inability to sustain profitability or achieve further growth.

Our operating results may fluctuate significantly depending upon various factors, which could make our future operating results difficult to predict and cause our operating results to fall below analysts’ and investors’ expectations.

Our operating results are difficult to predict due to a number of factors, particularly because we generally do not have long-term arrangements with buyers or sellers. We have from time to time experienced significant variations in revenue and operating results from period to period. Our operating results may continue to fluctuate and be difficult to predict due to a number of factors, including:

Because significant portions of our expenses are relatively fixed, variation in our quarterly revenue could cause significant variations in operating results and resulting stock price volatility from quarter to quarter. Our business has evolved significantly since our founding, and we expect the business to continue to evolve rapidly. Accordingly, period-to-period comparisons of our historical results of operations are not necessarily meaningful, and historical operating results may not be indicative of future performance. If our revenue or operating results fall below the expectations of investors or securities analysts, or below any guidance we may provide to the market, the price of our common stock could decline substantially.

Our revenue and operating results are highly dependent on the overall demand for advertising. Factors that affect the amount of advertising spending, such as economic downturns, particularly in the fourth quarter of our fiscal year, can make it difficult to predict our revenue and could adversely affect our business.

Our business depends on the overall demand for advertising and on the economic health of our current and prospective sellers and advertisers. If advertisers reduce their overall advertising spending, our revenue and results of operations are directly affected. Many advertisers devote a disproportionate amount of their advertising budgets to the fourth quarter of the calendar year to coincide with increased holiday purchasing, and buyers may spend more in the fourth quarter for budget reasons. As a result, if any events occur to reduce the amount of advertising spending during the fourth quarter, or reduce the amount of inventory available to advertisers during that period, it could have a disproportionate adverse effect on our revenue and operating results for that fiscal year. Economic downturns or instability in political or market conditions generally may cause current or new advertisers to reduce their advertising budgets. Reductions in inventory due to loss of sellers would make our solution less robust and attractive to buyers. Adverse economic conditions and general uncertainty about economic recovery are likely to affect our business prospects. In particular, uncertainty regarding the budget crisis in the United States may cause general business conditions in the United States and elsewhere to deteriorate or become volatile, which could cause advertisers to delay, decrease or cancel purchases of our solution, and expose us to increased credit risk on advertiser orders. Moreover, any changes in the favorable tax treatment of advertising expenses and the deductibility thereof would likely cause a reduction in advertising

demand. In addition, concerns over the sovereign debt situation in certain countries in the European Union as well as continued geopolitical turmoil in many parts of the world have and may continue to put pressure on global economic conditions, which could lead to reduced spending on advertising.

Seasonal fluctuations in digital advertising activity, which may historically have been less apparent due to our historical revenue growth, could adversely affect our cash flows and operating results.

Our managed revenue, revenue, cash flow from operations, operating results and other key operating and financial measures may vary from quarter to quarter due to the seasonal nature of advertiser spending. For example, many advertisers devote a disproportionate amount of their advertising budgets to the fourth quarter of the calendar year to coincide with increased holiday purchasing. Moreover, advertising inventory in the fourth quarter may be more expensive due to increased demand for advertising inventory. Seasonal fluctuations historically have been less apparent due to our historical revenue growth, but if our growth rate declines or seasonal spending becomes more pronounced, seasonality could result in material fluctuations of our revenue, cash flow, operating results and other key operating and financial measures from period to period.

Our corporate culture has contributed to our success, and if we cannot successfully maintain our culture as we assimilate new employees, we could lose the innovation, creativity and teamwork fostered by our culture.

We are undergoing rapid growth, including in our employee headcount. As of December 31, 2013, we had 344 employees, including 160 who were hired in 2013. A significant portion of our management team joined us in 2013. We expect that significant additional hiring will be necessary to support our strategic plans, including increased hiring in other countries. We have in the past added significant numbers of employees through acquisitions, and we may continue to do so. This rapid influx of large numbers of people from different business backgrounds may make it difficult for us to maintain our corporate culture. We believe our culture has contributed significantly to our ability to attract and retain talent, to acquire companies and to innovate and grow successfully. If our culture is negatively affected, our ability to support our growth and innovation may diminish.

Risks Related to the Advertising Technology Industry, Market and Competition

The digital advertising market is relatively new and dependent on growth in various digital advertising channels. If this market develops more slowly or differently than we expect, our business, growth prospects and financial condition would be adversely affected.

The digital advertising market is relatively new and our solution may not achieve or sustain high levels of demand and market acceptance. While display advertising has been used successfully for many years, marketing via new digital advertising channels, such as mobile and social media and digital video advertising, is not as well established. The future growth of our business could be constrained by the level of acceptance and expansion of emerging digital advertising channels, as well as the continued use and growth of existing channels, such as digital display advertising, in which our capabilities are more established. In addition, as we push for the expansion and adoption of increased automation in the advertising industry, it will be important for the success of any such expansion for personnel at buyers and sellers to adopt our solution in lieu of their traditional use of manual operations for order placement. It is difficult to predict adoption rates, demand for our solution, the future growth rate and size of the digital advertising solutions market or the entry of competitive solutions. Any expansion of the market for digital advertising solutions depends on a number of factors, including the growth of the digital advertising market, the growth of social, mobile and video as advertising channels and the cost, performance and perceived value associated with digital advertising solutions. If demand for digital display advertising and adoption of automation does not continue to grow, or if digital advertising solutions or advertising automation do not achieve widespread adoption, or there is a reduction in demand for digital advertising caused by weakening economic conditions, decreases in corporate spending or otherwise, or if we fail to develop capabilities to meet the needs of buyers and sellers of mobile and video advertising, our competitive position will be weakened and our revenue and results of operations could be harmed.

We operate in an intensely competitive market that includes companies that have greater financial, technical and marketing resources than we do.

We face intense competition in the marketplace. We are confronted by rapidly changing technology, evolving user needs and the frequent introduction by our competitors of new and enhanced solutions. We compete for advertising spending against competitors, including Google, who, in some cases, are also buyers on our platform. We also compete for supply of advertising inventory against a variety of competitors, including Google. Some of our existing and potential competitors are better established, benefit from greater name recognition, and have significantly more financial, technical, sales, and marketing resources than we do. In addition, some competitors, particularly those with a more diversified revenue base, may have greater flexibility than we do to compete aggressively on the basis of price and other contract terms. Some buyers that use our solution have their own relationships with sellers and can directly connect advertisers with sellers. Our business may suffer to the extent that buyers and sellers purchase and sell advertising inventory directly from one another or through intermediaries other than us. In addition, as a result of solutions introduced by us or our competitors in the rapidly evolving and fluid advertising market, our marketplace will experience disruptions and changes in business models, which may result in our loss of buyers or sellers. New competitors may emerge through acquisitions or through development of disruptive technologies. Strong and evolving competition could lead to a loss of our market share or compel us to reduce our prices and could make it more difficult to grow our business profitably.

We anticipate continued consolidation in the advertising technology industry, increasing the capabilities and competitive posture of larger companies and enabling new competitors to emerge. Many buyers and sellers are large consolidated organizations that may need to acquire other companies in order to grow. Smaller buyers and sellers may need to consolidate in order to compete effectively. There is a finite number of large buyers and sellers in our target markets, and as technology continues to improve and market factors continue to compel investment by others in the business, market saturation may change the competitive landscape in favor of larger competitors with greater scale. Moreover, any consolidation of buyers or sellers may give the resulting enterprises greater bargaining power or result in the loss of buyers and sellers that use our platform, and thus reduce our potential base of buyers and sellers, each of which would lead to erosion of our revenue.

Our business depends on our ability to collect and use data to deliver advertisements, and to disclose data relating to the performance of advertisements. Any limitation imposed on our collection, use or disclosure of this data could significantly diminish the value of our solution and cause us to lose sellers, buyers and revenue.

When advertisements are placed through our solution, we are able to collect anonymous information about the placement of the advertisement and the interaction of the device user with the advertisement, such as whether the user visited a landing page or watched a video. We are also able to collect information about pricing of advertisements, historical clearing prices, bid responses, what types of advertisements are allowed on a particular website, which websites a buyer prefers, what ad formats are available to be served, advertisement size and location, where a user is located, how many advertisements has the user seen, browser or device information and sellers’ proprietary data about users. As we collect and aggregate this data provided by trillions of advertising impressions, we analyze it in order to facilitate optimization of the pricing, placement and scheduling of advertisements purchased by buyers across the advertising inventory provided by sellers.

Sellers or Internet users might decide not to allow us to collect some or all of the data we collect or might limit our use of it. For example, a seller might not agree to provide us with data generated by interactions with the content on its applications, or device users might not consent to share their information about device usage. Any limitation on our ability to collect data about user behavior and interaction with content could make it more difficult for us to deliver effective solutions that meet the needs of sellers and advertisers. This in turn could hurt our revenue and impair our business.

Although our contracts with sellers generally permit us to aggregate data from advertising placements, sellers in the future may prohibit the collection or use of this data or request that we discontinue using data

obtained from their transactions that has already been aggregated with other data. It would be difficult, if not impossible, and costly to comply with these requests. Interruptions, failures or defects in our data collection, mining, analysis and storage systems, as well as privacy concerns and regulatory obligations regarding the collection, use and processing of data, could also limit our ability to aggregate and analyze the data from transactions effected through our solution. Restrictions or limitations on our use of data could reduce the utility and value of our solution, resulting in loss of volume and reduced pricing.

If the use of “third party cookies” is restricted or otherwise subject to unfavorable regulation, our performance may decline and we may lose advertisers and revenue.

We use “cookies,” or small text files, to gather data to enable our solution to be more effective. Cookies that we place are generally regarded as “third party cookies” because they are placed on individual browsers when Internet users visit a website owned by a seller, advertiser or other first party that has given us permission to place cookies. These cookies are placed through an Internet browser on an Internet user’s computer and correspond with a data set that we keep on our servers. Our cookies record non-personal information, such as when an Internet user views an advertisement, clicks on an advertisement, where a user is located, how many advertisements the user has seen and browser or device information. We may also receive information from cookies placed by advertisers or other parties who give us permission to use their cookies. We use data from cookies to help buyers decide whether to bid on, and how to price, an opportunity to place an advertisement in a certain location, at a given time, in front of a particular Internet user. Without cookie data, transactions occurring through our solution would be executed with less insight into activity that has taken place through an Internet user’s browser, reducing the ability of buyers to make accurate decisions about which inventory to purchase for an advertiser’s campaign. This could make placement of advertising through our solution less valuable, with commensurate reduction in pricing. In addition to cookies, we sometimes place pixels on seller websites to track data regarding users’ visits to such websites. We may use such information internally to optimize our services, and may provide such data, or analyses based on such data, to buyers or sellers as part of our services. If sellers restrict our ability to place such pixels on their websites, or if the use of such tracking mechanisms is restricted by laws in the future, it may diminish the value of our services.

In addition, in the European Union, or EU, Directive 2009/136/EC, commonly referred to as the “Cookie Directive,” directs EU member states to ensure that accessing information on an Internet user’s computer, such as through a cookie, is allowed only if the Internet user has given his or her consent. In response, some member states have adopted and implemented, and may continue to adopt and implement legislation that negatively impacts the use of cookies for digital advertising.

Limitations on the use or effectiveness of cookies, whether imposed by regulation or otherwise, may impact the performance of our solution. We may be required to, or otherwise may determine that it is advisable to, develop or obtain additional applications and technologies to compensate for the lack of cookie data, which may require substantial investment on our part. However, we may not be able to develop or implement additional applications that compensate for the lack of cookie data. Moreover, even if we are able to do so, such additional applications may be subject to further regulation, time consuming to develop or costly to obtain, and less effective than our current use of cookies.

Prominent sellers have announced plans to replace cookies with alternative mechanisms, and if cookies are discontinued in favor of proprietary tracking mechanisms, our costs to develop alternatives could increase, our ability to optimize advertisements may suffer, and we may be placed at a competitive disadvantage to others that utilize proprietary user tracking mechanisms.

Google and Microsoft have announced intentions to discontinue the use and deployment of cookies, and to develop alternative methods and mechanisms for tracking web users. There are also reports that other prominent web sellers, such as Amazon, Facebook, and Apple, are also developing alternative web tracking technologies to displace the use of cookies. These alternative mechanisms have not been described in technical detail, and have not been announced with any specific stated time line. It is possible that these companies may rely on proprietary

algorithms or statistical methods to track web users without the deployment of cookies, or may utilize log-in credentials entered by users into other web properties owned by these companies, such as their digital email services, to track web usage without deploying third party cookies. Alternatively, such companies may build alternative and potentially proprietary user tracking methods into their widely-used web browsers.

If cookies are effectively replaced by proprietary alternatives, any continued attempt by us to use cookie-based methods may face negative consumer sentiment and otherwise place us at a competitive disadvantage. If cookies are replaced, in whole or in part, by proprietary alternatives, we would need to develop alternative proprietary tracking methodologies, which would require substantial investment from us, or which may not be commercially feasible given our relatively small size and the fact that development of such technologies may require technical skills that differ from our core engineering competencies. If we find that the development of alternative tracking methodologies is not feasible, we may be effectively obligated to license proprietary tracking mechanisms and data from companies that have developed them, which also compete with us as advertising networks, and we may only be able to obtain such licenses on economically and operationally unfavorable terms. If such proprietary web tracking standards are owned by companies that compete with us they may be unwilling to make such technology available to us. Further, if such proprietary web tracking standards are owned by sellers or browser operators that have access to user information by virtue of their popular consumer-oriented websites or browsers and have the technology designed for use in conjunction with the types of user information collected from their websites, we may still be at a competitive disadvantage even if we license their technology.

If cookies are effectively replaced by tracking technologies that are adopted as open industry-wide standards rather than proprietary standards, we may still incur substantial costs to replace cookie-based tracking mechanisms with these new tracking technologies. This may impose substantial re-engineering costs, and may also diminish the quality or value of our services to advertisers, if such new web-tracking technologies do not provide us with the quality or timeliness of the tracking data that we currently generate from cookies.

If the use of “third party cookies” or digital advertising generally is rejected by Internet users, our performance may decline and we may lose advertisers and revenue.

Cookies may easily be deleted or blocked by Internet users. All of the most commonly used Internet browsers (Chrome, Firefox, Internet Explorer, and Safari) allow Internet users to modify their browser settings to prevent first party or third party cookies from being accepted by their browsers. Most browsers also now support temporary privacy modes that allow the user to suspend, with a single click, the placement of new cookies or reading or updates of existing cookies. Internet users can also delete cookies from their computers at any time. Some Internet users also download free or paid “ad blocking” software that prevents third party cookies from being stored on a user’s computer. If more Internet users adopt these ad blocking settings, utilize privacy modes when browsing seller websites, or delete their cookies more frequently than they currently do, our business could be harmed. In addition, the Safari browser blocks third party cookies by default, as do Apple’s iPad and iPhones. Many applications and other devices offer paid subscriptions or other paid downloads to users who do not wish to receive advertisements. The browser manufacturer, Mozilla, which publishes Firefox, recently announced an intention to block third party cookies by default in the next iteration of the Firefox browser. Mobile devices based upon the Android operating system use cookies only in their web browser applications, so that cookies do not track Android users while they are using other applications on the device. As a consequence, fewer of our cookies or sellers’ cookies may be set in browsers or accessible in mobile devices, which adversely affects our business.

“Do Not Track” options in web browsers, as well as emerging government disclosure obligations and other potential regulations, could negatively impact our business by limiting our access to the anonymous user data that informs the advertising campaigns transacted through our solution, and as a result may degrade our performance for our advertisers or sellers.

Current versions of the most widely used web browsers such as Chrome, Firefox, Internet Explorer and Safari allow users to send “Do Not Track” messages, whereby users indicate that they do not wish to have their

web usage tracked. However, there are currently no definitions of “tracking” and no standards regarding how to respond to a “Do Not Track” preference that are accepted or standardized in the industry. The World Wide Web Consortium chartered a “Tracking Protection Working Group” in 2011 to convene a multi-stakeholder group of academics, thought leaders, companies, industry groups and consumer advocacy organizations, to create a voluntary “Do Not Track” standard for the web, but this effort appears to be disbanding, without having agreed upon a standard. The Federal Trade Commission, or FTC, has previously stated that it will pursue a legislative solution if the industry does not agree to a standard.

Effective January 1, 2014, amendments to the California Online Privacy Protection Act of 2003, California Business and Professional Code § 22575 et seq., require operators of websites or online services to disclose how the operator responds to “Do Not Track” signals regarding the collection of personally identifiable information about an individual consumer’s online activities over time and across third-party Web sites or online services, as well as to disclose whether third parties may collect personally identifiable information about an individual consumer’s online activities over time and across different Web sites or online services. It is possible that other states could adopt legislation similar to California’s. The “Do-Not-Track Online Act of 2013” was introduced in the United States Senate in February 2013, and it is possible that the federal government may adopt Do Not Track legislation. We may be subject to disclosure requirements such as California’s, and while we do not collect data that is traditionally considered personally identifiable information in the United States, we may nonetheless elect to respond by adopting a policy to discontinue profiling or web tracking in response to “Do Not Track” requests, and it is possible that we could in the future be prohibited from using non-personal consumer data by industry standards or state or federal legislation, which may diminish our ability to optimize and target advertisements, and the value of our services.

Legislation and regulation of digital businesses, including privacy and data protection regimes, could create unexpected additional costs, subject us to enforcement actions for compliance failures, or cause us to change our technology solution or business model, which may have an adverse effect on the demand for our solution.

In the course of our business, we collect, store, transmit, and use information (including geo-location information) related to computing and communications devices (mobile and stationary), user activity on devices, and advertisements placed through our solution. U.S. and foreign governments have enacted or are considering legislation related to digital advertising and we expect to see an increase in legislation and regulation related to digital advertising, the use of geo-location data to inform advertising, the collection and use of anonymous Internet user data and unique device identifiers, such as IP address or mobile unique device identifiers, and other data protection and privacy regulation. Such legislation could affect the costs of doing business online, and may adversely affect the demand for or effectiveness and value of our solution.

We strive to comply with all applicable laws and regulations relating to privacy and data collection, processing, use and disclosure, but these laws and regulations are continually evolving, not always clear, and not always consistent across the jurisdictions in which we do business. We are aware of several ongoing lawsuits filed against companies in the digital advertising industry alleging various violations of consumer protection and computer crime laws, asserting various privacy-related theories. Any such proceedings brought against us could hurt our reputation, force us to spend significant amounts in defense of these proceedings, distract our management, increase our costs of doing business, adversely affect the demand for our services and ultimately result in the imposition of monetary liability or restrictions on our ability to conduct our business. We may also be contractually liable to indemnify and hold harmless buyers or sellers from the costs or consequences of litigation resulting from using our services or from the disclosure of confidential information, which could damage our reputation among our current and potential sellers, buyers or advertisers, require significant expenditures of capital and other resources and cause us to lose business and revenue.

A wide variety of local, state, national and international laws and regulations apply to the collection, use, retention, protection, disclosure, transfer and other processing of data collected from and about consumers and devices, and the regulatory framework for privacy issues is evolving worldwide. Various government and

consumer agencies and public advocacy groups have called for new regulation and changes in industry practices,

including some directed at the digital advertising industry in particular. Some of our competitors may have more access to lobbyists or governmental officials and may use such access to effect statutory or regulatory changes in a manner to commercially harm us while favoring their solutions. It is possible that new laws and regulations will be adopted in the United States and internationally, or existing laws and regulations may be interpreted in new ways, that would affect our business, particularly with regard to collection or use of data to target advertisements and communication with consumers through mobile devices and/or using location and the collection of data from apps and websites that are targeted to children. The U.S. government, including the FTC and the Department of Commerce, has announced that it is reviewing the need for greater regulation of the collection of consumer information, including regulation aimed at restricting some targeted advertising practices. The FTC has also adopted revisions to the Children’s Online Privacy Protection Act that expand liability for the collection of information (including certain anonymous information such as persistent identifiers) by operators of websites and other online services that are directed to children or that otherwise use information collected from or about children. In addition, the European Union has adopted the EU e-Privacy Directive and is in the process of proposing reforms to its existing data protection legal framework, which may result in a greater compliance burden for us in the course of delivering our solution in Europe. Complying with any new regulatory requirements could force us to incur substantial costs or require us to change our business practices in a manner that could reduce our revenue or compromise our ability to effectively pursue our growth strategy.

We take measures to protect the security of information that we collect, use and disclose in the operation of our business, and to offer certain privacy protections with respect to such information, but such measures may not always be effective. Our failure to comply with applicable laws and regulations or industry standards applicable to personal data or other data relating to consumers, or to protect such data, could result in enforcement action against us, including fines, imprisonment of our officers and public censure, claims for damages by consumers and other affected individuals, damage to our reputation and loss of goodwill. Even the perception of concerns relating to our collection, use, disclosure, and retention of data, including our security measures applicable to the data we collect, whether or not valid, may harm our reputation and inhibit adoption of our solution by current and future buyers and sellers.

The European Parliament is considering revocation of the EU—U.S. Safe Harbor Framework, under which personal data of EU residents may be transferred to the United States, and this revocation, if implemented, could hamper our plans to expand our business in Europe.

The use and transfer of personal data in EU member states is currently governed under Directive 95/46/EC (which is commonly referred to as the Data Protection Directive) as well as legislation adopted in the member states to implement the Data Protection Directive. The transfer of what is deemed to be personal data of EU subjects is currently permitted under a process agreed to by the EU and the United States known as the EU—U.S. Safe Harbor Framework, pursuant to which U.S. businesses commit to treat the personal data of EU residents in accordance with privacy principles promulgated by the Data Protection Directive, and may self-certify their compliance with the Safe Harbor Framework. The EU is currently considering adoption of a General Data Protection Regulation, to supersede the Data Protection Directive, and a European Parliament Inquiry has recently indicated that it will recommend suspension of the Safe Harbor Framework as part of the General Data Protection Regulation. Meanwhile, the European Commission recently published its analysis of the Safe Harbor Framework and concluded that it should be revised to include greater transparency and active enforcement. If restrictions are adopted by the EU that prohibit the transfer of our data regarding EU subjects to our computer servers in the U.S., we may have to create duplicative, and potentially expensive, information technology infrastructure and business operations in Europe, which may hinder our expansion plans in Europe, or render such plans commercially infeasible.

Changes to the definition of personal information or personal data, as well as jurisdictional variances regarding what constitutes personal information or personal data, may require us to change our business practices, which may inhibit our ability to conduct our business.

Although we do not collect data that is traditionally considered personal data in the United States, such as names, email addresses, addresses, phone numbers, social security numbers, credit card numbers, financial or

health data in the ordinary course of providing our solution (except to the limited extent personal data is voluntarily submitted by a user with knowledge and consent through our website), we typically do collect and store IP addresses, geo-location information, and other device identifiers that are or may be considered personal data in some jurisdictions or otherwise may be the subject of legislation or regulation. For example, the EU generally regards IP addresses as personal data.

Evolving definitions of personal data, within the EU, the United States and elsewhere, especially relating to the classification of IP addresses, machine or device identifiers, location data and other such information, may cause us in the future to change our business practices, diminish the quality of our data and the value of our solution, and hamper our ability to expand our offerings into the EU or other jurisdictions outside of the United States.

If mobile connected devices or any other devices, their operating systems, Internet browsers or content distribution channels, including those controlled by our competitors, develop in ways that prevent advertisements from being delivered to their users, our ability to grow our business will be impaired.

Our success in the mobile channel depends upon the ability of our technology solution to provide advertising for most mobile connected devices, as well as the major operating systems or Internet browsers that run on them and the thousands of applications that are downloaded onto them. The design of mobile devices and operating systems or Internet browsers is controlled by third parties with whom we do not have any formal relationships. These parties frequently introduce new devices, and from time to time they may introduce new operating systems or Internet browsers or modify existing ones. Network carriers may also impact the ability to access specified content on mobile devices. If our solution is unable to work on these devices, operating systems or Internet browsers, either because of technological constraints or because a maker of these devices or developer of these operating systems or Internet browsers wished to impair our ability to provide advertisements on them or our ability to fulfill advertising inventory from developers whose applications are distributed through their controlled channels, our ability to generate revenue could be significantly harmed.

Changes in tax laws affecting us and other market participants could have a material adverse effect on our business.

U.S. legislative proposals have been made that, if enacted, would limit or delay the deductibility of advertising costs for U.S. federal income tax purposes. Any such proposals, if enacted, will likely cause advertisers to reduce their advertising spending in order to mitigate or offset any loss resulting from a change in the tax treatment of such costs. Accordingly, any such changes would likely have a negative impact on the advertising industry and us by reducing the aggregate amount of money spent on advertising.

U.S. legislation has also been proposed that would limit the ability to defer taxation for U.S. federal income tax purposes of earnings outside the United States until those earnings are repatriated. Any changes in the taxation of our non-U.S. earnings could increase our tax expense and harm our financial position and results of operations.

We generally do not have privity with Internet users who view advertisements that we place, and we may not be able to disclaim liabilities from such Internet users or consumers.

Advertisements on websites, applications and other digital media properties of sellers purchased through our solution are viewed by Internet users visiting these digital media properties. Sellers often have terms of use in place with their users that disclaim or limit their potential liabilities to such users, or pursuant to which users waive rights to bring class-actions against the sellers. Certain of our competing advertisement networks are also prominent sellers, and may be able to include protections in their website terms of use that also limit liability to users for their advertising services. We generally do not have terms of use in place with such users. As a consequence, we generally cannot disclaim or limit potential liabilities to such users through terms of use, which may expose us to greater liabilities than competing advertising networks that are also prominent sellers.

Changes in market standards applicable to our solution could require us to incur substantial additional development costs.

Market forces, competitors’ initiatives, regulatory authorities, industry organizations, seller integration revisions and security protocols are causing the emergence of demands and standards that are or could be applicable to our solution. For example, in 2013, changes to the Children’s Online Privacy Protection Act required us to change our system to stop user tracking on some seller websites. In addition, German law required us to make engineering changes to stop tracking IP addresses in that country. Consensus or law on a “do not track” standard could require us to stop tracking of many Internet users. Similar dynamics are evolving in international markets.

We expect compliance with these kinds of standards to become increasingly important to buyers and sellers, and conforming to these standards is expected to consume a substantial and increasing portion of our development resources. If our solution is not consistent with emerging standards, our market position and sales could be impaired. If we make the wrong decisions about compliance with these standards, or are late in conforming, or if despite our efforts our solution fails to conform, our offerings will be at a disadvantage in the market to the offerings of competitors who have complied.

Failure to comply with industry self-regulation could harm our brand, reputation and our business.

In addition to compliance with government regulations, we voluntarily participate in trade associations and industry self-regulatory groups that promulgate best practices or codes of conduct addressing privacy and the provision of Internet advertising. For example, we have undertaken to comply with the Network Advertising Initiative’s Code of Conduct and the Digital Advertising Alliance’s Self-Regulatory Principles for Online Behavioral Advertising in the United States, as well as similar self-regulatory principles in Europe adopted by the Interactive Advertising Bureau—Europe and the European Digital Advertising Alliance. On our website, we offer Internet users the ability to opt out of receiving interest-based advertisements based on a cookie we place. However, in the past, some of these guidelines have not comported with our business practices, making them difficult for us to implement. If we encounter difficulties in the future, or our opt-out mechanisms fail to work as designed, or if Internet users misunderstand our technology or our commitments with respect to these principles, we may, as a result, be subject to investigation and litigation by governmental authorities, self-regulatory bodies or other accountability groups, buyers, sellers, or other private parties, in addition to experiencing negative publicity. Any such action against us could be costly and time consuming, require us to change our business practices, cause us to divert management’s attention and our resources, and be damaging to our reputation and our business. In addition, we could be adversely affected by new or altered self-regulatory guidelines that are inconsistent with our practices or in conflict with applicable laws and regulations in the United States and other countries where we do business. As a result of such inconsistencies or conflicts, or other business or legal considerations, we may choose not to comply with some self-regulatory guidelines. If we fail to abide by or are perceived as not operating in accordance with applicable laws and regulations and industry best practices or any industry guidelines or codes with regard to privacy or the provision of Internet advertising, our reputation may suffer and we could lose relationships with buyers and sellers.

The forecasts of market growth, as described in this prospectus, may prove to be inaccurate, and even if the market in which we compete achieves the forecasted growth, we cannot assure you our business will grow at similar rates, if at all.

Growth forecasts are subject to significant uncertainty and are based on assumptions and estimates that may prove to be inaccurate. The forecasts in this prospectus relating to the expected growth in the digital advertising market and parts of that market (including display, mobile and digital video advertising), as well as the forecasted trend towards automation of analog and print advertising markets may prove to be inaccurate. Moreover, the anticipation that the advertising industry will continue to shift from analog and print media to digital advertising at the rate forecasted or the anticipation of the shift in advertising spending from analog to digital may not come to fruition. Further, we may not succeed in our plans to enter or increase our presence in various markets for various reasons, including possible shortfall or misallocation of resources or superior technology development or marketing by competitors.

Risks Related to Our Relationships with Buyers and Sellers and Other Strategic Relationships

We depend on owners of digital media properties for advertising inventory to deliver advertisers’ advertising campaigns, and any decline in the supply of advertising inventory from these sellers could hurt our business.

We depend on digital media properties to provide us with advertising inventory within their websites and applications. The sellers that supply their advertising inventory to us typically do so on a non-exclusive basis and are not required to provide any minimum amounts of advertising inventory to us, or provide us with a consistent supply of advertising inventory. Sellers may seek to change the terms at which they offer inventory to us, or they may elect to make advertising inventory available to our competitors who offer advertisements to them on more favorable economic terms. Supply of advertising inventory is also limited for some sellers, such as special sites or new technologies, and sellers may request higher prices, fixed price arrangements or guarantees. In addition, sellers sometimes place significant restrictions on the sale of their advertising inventory. These restrictions may include restrictive security requirements, prohibit advertisements from specific advertisers or specific industries, or restrict the use of specified creative content or format. In addition, sellers or competitors could pressure us to increase the prices for inventory, which may reduce our operating margins, or otherwise block our access to that inventory, without which we would be unable to deliver advertisements using our solution.

If sellers decide not to make advertising inventory available to us, decide to increase the price of inventory, or place significant restrictions on the sale of their advertising inventory, we may not be able to replace this with inventory from other sellers that satisfies our requirements in a timely and cost-effective manner. In addition, significant sellers in the industry may enter into exclusivity arrangements with our competitors, which could limit our access to a meaningful supply of advertising inventory. If any of this happens, the value of our solution to buyers could decrease and our revenue could decline or our cost of acquiring inventory could increase, lowering our operating margins.

Our contracts with buyers are generally not exclusive and generally do not require minimum volumes or long-term commitments. If a buyer, or group of buyers, representing a significant portion of our business decides to materially reduce the use of our solution we could experience an immediate and significant decline in our revenue and profitability and harm our business.

Generally, buyers conduct business with our competitors as well as with us, and are not obligated to provide us with any minimum volumes of business. Most of our business with buyers originates pursuant to “insertion orders,” which are often limited in scope and can be reduced or canceled by the buyer without penalty. Accordingly, our business is highly vulnerable to changes in the macro environment and development of new or more compelling offerings by our competitors, which could reduce business generally or motivate buyers to migrate to competitors’ offerings. Further, if our relationship with a buyer becomes strained due to service failures or other reasons, it is very easy for that buyer to reduce or terminate its business with us. Because we do not have long-term contracts, our future revenue may be difficult to predict and there is no assurance that our current buyers will continue to use our solution or that we will be able to replace lost buyers with new ones. Additionally, if we overestimate future usage, we may incur additional expenses in adding infrastructure, without a commensurate increase in revenue, which would harm our profitability and other operating results. If a buyer or group of buyers representing a significant portion of our business decides to materially reduce use of our solution, it could cause an immediate and significant decline in our revenue and profitability and harm our business.

Loss of business associated with large buyers or sellers could have significant negative impact on our results of operations and overall financial condition.

Certain large buyers and sellers have accounted for and will continue to account for a disproportionate share of business transacted through our solution. Consequently, the retention of large buyers and sellers is important to our operating results as well as the robustness of our exchange. Our contracts with buyers and sellers generally do not provide for any minimum volumes or may be terminated on relatively short notice. Buyer and seller needs

and plans can change quickly, and buyers or sellers may reduce volumes or terminate their arrangements with us for a variety of reasons, including financial issues or other changes in circumstances, new offerings by or strategic relationships with our competitors, change in control (including consolidations through mergers and acquisitions), or declining general economic conditions (including those resulting from dissolutions of companies). Technical issues could also cause a decline in spending. The number of large media buyers in the market is finite, and it could be difficult for us to replace revenue loss from any buyers whose relationships with us diminish or terminate. Similarly, it could be difficult for us to replace inventory loss from any large sellers whose relationships with us diminish or terminate. Just as growth in our inventory strengthens buyer activity in a network effect, loss of inventory or buyers could have the opposite effect. Loss of revenue from significant buyers or failure to collect accounts receivable, whether as a result of buyer payment default, contract termination, or other factors, or significant reductions in inventory, could have a significant negative impact on our results of operation and overall financial condition.

We rely on buyers to use our solution to purchase advertising on behalf of advertisers. Such buyers may have or develop high-risk credit profiles, which may result in credit risk to us.

Our revenue is generated from advertising spending transacted over our platform using our technology solution. We invoice and collect from the buyer the full purchase price for impressions they have purchased, retain our fees, and remit the balance to the sellers. However, in some cases, we may be required to pay sellers for impressions delivered even if we are unable to collect from the buyer of those impressions. There can be no assurances that we will not experience bad debt in the future. Any such write-offs for bad debt could have a materially negative effect on our results of operations for the periods in which the write-offs occur.

Our sales efforts with buyers and sellers may require significant time and expense.

Attracting new buyers and sellers and increasing our business with existing buyers and sellers involves substantial time and expense, and we may not be successful in establishing new relationships or in maintaining or advancing our current relationships. We may spend substantial time and effort educating buyers and sellers about our offerings, including providing demonstrations and comparisons against other available solutions. This process can be costly and time-consuming, and is complicated by us having to spend time integrating our solution with software of buyers and sellers. Because our solution may be less familiar in some markets outside the United States, the time and expense involved with attracting, educating and integrating new markets may be even greater in other markets. If we are not successful in targeting, supporting and streamlining our sales processes, our ability to grow our business may be adversely affected.

If we are unable to maintain or expand our sales and marketing capabilities, we may not be able to generate anticipated revenue.

Increasing our base of buyers and sellers and achieving broader market acceptance of our solution will depend to a significant extent on our ability to expand our sales and marketing operations and activities. We are substantially dependent on our sales force to obtain new buyers and sellers and to drive sales to our existing buyers. We currently plan to expand our sales team in order to increase revenue from new and existing buyers and sellers and to further penetrate our existing markets and expand into new markets, such as mobile, digital video and international markets. Our solution requires a sophisticated sales force with specific sales skills and specialized technical knowledge that takes time to develop. Competition for qualified sales personnel is intense, and we may not be able to retain our existing sales personnel or attract, integrate or retain sufficient highly qualified sales personnel. In particular, it may be difficult to find qualified sales personnel in international markets, or sales personnel with experience in emerging segments of the market, such as mobile and digital video. Our ability to achieve revenue growth in the future will depend, in large part, on our success in recruiting, training and retaining sufficient numbers of sales personnel. These new employees require significant training and experience before they achieve full productivity. We estimate that it takes approximately six months before a newly hired domestic sales representative is fully trained and productive in selling our solution, and often longer

in the case of foreign sales representatives and sales personnel focused on new geographies or specific market segments. As a result, the cost of hiring and carrying new representatives cannot be offset by the revenue they produce for a significant period of time. Our recent hires and planned hires may not become productive as quickly as we would like, and we may not be able to hire or retain sufficient numbers of qualified individuals in the markets where we do business. Our business will be seriously harmed if these expansion efforts do not generate a corresponding significant increase in revenue.

Legal claims resulting from the actions of buyers or sellers could expose us to liabilities, damage our reputation, and be costly to defend.

The buyers and sellers engaging in transactions through our platform impose various requirements upon each other, and they and the underlying advertisers are subject to regulatory requirements by governments and standards bodies applicable to their activities. We assume responsibility for satisfying or facilitating the satisfaction of some of these requirements through the contracts we enter into with buyers and sellers. In addition, we may have responsibility for some acts or omissions of buyers or sellers transacting business through our solution under applicable laws or regulations or as a result of common law duties, even if we have not assumed responsibility contractually. These responsibilities could expose us to significant liabilities, perhaps without the ability to impose effective mitigating controls upon or to recover from buyers and sellers. Moreover, for those third parties who are both a buyer and seller on our platform, it is feasible that they could use our platform to buy and sell advertisements in an effort to inflate their own revenue. While we do not believe we would have legal liability in connection with such a scheme, we could still nevertheless be subject to litigation as a result of such actions, and, if we were sued, we would incur legal costs in our defense and cannot guarantee that a court would not attribute some liability to us.

We generally attempt to obtain representations from buyers that the advertising they place through our solution complies with applicable laws and regulations and does not violate third-party intellectual property rights, and from sellers about the quality and characteristics of the impressions they provide. We also generally receive representations from buyers and sellers about their privacy practices and compliance with applicable laws and regulations, including their maintenance of adequate privacy policies that disclose and permit our data collection practices. However, we are not always able to verify or control their compliance with their obligations under their agreements with or to consumers or other third parties, and the acts or omissions of sellers, buyers or advertisers may subject us to regulatory action, legal claims, and liability that would be difficult and costly to defend and expose us to significant costs and reputational harm. We may not have adequate indemnity to protect us against, and our policies of insurance may not cover such claims and losses.

Our business relationships expose us to risk of substantial liability for contract breach, violation of laws and regulations, intellectual property infringement and other losses, and our contractual indemnities and limitations of liability may not protect us adequately.

Our agreements with sellers, buyers, and other third parties typically obligate us to provide indemnity and defense for losses resulting from claims of intellectual property infringement, damages to property or persons, business losses, or other liabilities. Generally these indemnity and defense obligations relate to our own business operations, obligations, and acts or omissions. However, under some circumstances, we agree to indemnify and defend contract counterparties against losses resulting from their own business operations, obligations, and acts or omissions, or the business operations, obligations, and acts or omissions of third parties. For example, because our business interposes us between buyers and sellers in various ways, buyers often require us to indemnify them against acts and omissions of sellers, and sellers often require us to indemnify them against acts and omissions of buyers. In addition, our agreements with sellers, buyers, and other third parties typically include provisions limiting our liability to the counterparty, and the counterparty’s liability to us. These limits sometimes do not apply to certain liabilities, including indemnity obligations. These indemnity and limitation of liability provisions generally survive termination or expiration of the agreements in which they appear.

We have limited ability to control acts and omissions of buyers and sellers or other third parties that could trigger our indemnity obligations, and our policies of insurance may not cover us for acts and omissions of others. We attempt to obtain indemnity from buyers and sellers (as well as other third parties), to protect us in case we become liable for their acts and omissions, but because we contract with many buyers and sellers and those contracts are individually negotiated with different scopes of indemnity and different limits of liability, it is possible that in any case our obligation to provide indemnity for the acts or omissions of a third party such as a buyer or seller may exceed what we are able to recover from that party. Further, contractual limits on our liability may not apply to our indemnity obligations, contractual limits on our counterparties’ liability may limit what we can recover from them, and contract counterparties may be unable to meet their obligations to indemnify and defend us as a result of insolvency or other factors. Large indemnity obligations, or obligations to third parties not adequately covered by the indemnity obligations of our contract counterparties, could expose us to significant costs.

In addition to the effects on indemnity described above, the limitation of liability provisions in our contracts may, depending upon the circumstances, be too high to protect us from significant liability for our own acts or omissions, or so low as to prevent us from recovering fully for the acts or omissions of our counterparties.

Our solution relies on third-party open source software components. Failure to comply with the terms of the underlying open source software licenses could expose us to liabilities, and the combination of certain open source software with code that we develop could compromise the proprietary nature of our solution.

Our solution utilizes software licensed to us by third-party authors under “open source” licenses. The use of open source software may entail greater risks than the use of third-party commercial software, as open source licensors generally do not provide warranties or other contractual protections regarding infringement claims or the quality of the code. Some open source licenses contain requirements that we make available source code for modifications or derivative works we create based upon the type of open source software we use. If we combine our proprietary software with open source software in a certain manner, we could, under certain open source licenses, be required to release the source code of our proprietary software to the public. This would allow our competitors to create similar solutions with lower development effort and time and ultimately put us at a competitive disadvantage.

Although we monitor our use of open source software in an effort to avoid subjecting our products to conditions we do not intend, the terms of many open source licenses have not been interpreted by U.S. courts, and there is a risk that these licenses could be construed in a way that could impose unanticipated conditions or restrictions on us. Moreover, we cannot guarantee that our processes for controlling our use of open source software will be effective. If we are held to have breached the terms of an open source software license, we could be required to seek licenses from third parties to continue operating using our solution on terms that are not economically feasible, to re-engineer our solution or the supporting computational infrastructure to discontinue use of certain code, or to make generally available, in source code form, portions of our proprietary code.

Real or perceived errors or failures in the operation of our solution could damage our reputation and impair our sales.

Our solution processes more than 2.5 million peak queries per second and approximately 3 trillion bid requests per month and must operate without interruption to support the needs of sellers and buyers. Because our software is complex, undetected errors and failures may occur, especially when new versions or updates are made to our software or network infrastructure or changes are made to sellers’ or buyers’ software interfacing with our solution. Errors or bugs in our software, faulty algorithms, technical or infrastructure problems, or updates to our systems could lead to an inability to process data to place advertisements or price inventory effectively, or cause advertisements to display improperly or be placed in proximity to inappropriate content.

Despite testing by us, errors or bugs in our software have in the past, and may in the future, not be found until the software is in our live operating environment. For example, changes to our solution have in the past caused errors in the reporting and analytics applications for buyers, resulting in delays in their spending on our platform. Errors or failures in our solution, even if caused by the implementation of changes by buyers or sellers to their systems, could also result in negative publicity, damage to our reputation, loss of or delay in market acceptance of our solution, increased costs or loss of revenue, loss of competitive position or claims by advertisers for losses sustained by them.

We may make errors in the measurement of transactions conducted through our solution, causing discrepancies with the measurements of buyers and sellers, which can lead to a lack in confidence in us and require us to reduce our fees or provide refunds to buyers and sellers. Alleviating problems resulting from errors in our software could require significant expenditures of capital and other resources and could cause interruptions, delays or the cessation of our business.

Various risks could interrupt access to our network infrastructure or data, exposing us to significant costs and other liabilities.

Our revenue depends on the technological ability of our solution to deliver and measure advertising impressions, and the operation of our exchange and our ability to place impressions depend on the continuing and uninterrupted performance of our IT systems. Our platform operates on our data processing equipment that is housed in third-party commercial data centers that we do not control. In addition, our systems interact with systems of buyers and sellers and their contractors. All of these facilities and systems are vulnerable to interruption and/or damage from a number of sources, many of which are beyond our control, including, without limitation: (i) power loss, loss of adequate cooling and telecommunications failures; (ii) fire, flood, earthquake, hurricane and other natural disasters; (iii) software and hardware errors, failures or crashes; (iv) financial insolvency; and (v) computer viruses, hacking, terrorism, and similar disruptive problems. In particular, intentional cyber-attacks present a serious issue because of the difficulty associated with prevention and remediation of intentional attacks and sabotage, and because they can be used to steal confidential or proprietary data from us or our users. Further, because our Los Angeles headquarters and San Francisco office and our California and Japan data center sites are in seismically active areas, earthquakes present a particularly serious risk of business disruption. These vulnerabilities may increase with the complexity and scope of our systems and their interactions with buyer and seller systems.

We attempt to mitigate these risks to our business through various means, including redundant infrastructure, disaster recovery plans, separate test systems and change control and system security measures, but our precautions may not protect against all problems, and our ability to mitigate risks to related third-party systems is limited. In addition, we rely to a significant degree upon security and business continuity measures of our data center operators, which may be ineffective. Our disaster recovery and business continuity plans rely upon third-party providers of related services, and if those vendors fail us, we could be unable to meet the needs of buyers and sellers. Any steps we take to increase the reliability and redundancy of our systems may be expensive and may not be successful in preventing system failures. Inaccessibility of our data would have a significant adverse effect upon the operation of our solution. Any failures with our solution or delays in the execution of transactions through our system may result in the loss of advertising placements on impressions and, as a result, the loss of revenue. Our facilities would be costly to repair or replace, and any such efforts would likely require substantial time.

Buyers may perceive any technical disruption or failure in the performance of advertisements on seller’s digital media properties to be attributable to us, and our reputation could similarly suffer, or buyers may seek to avoid payment or demand future credits for disruptions or failures, any of which could harm our business and results of operations. If we are unable to operate our exchange and deliver advertising impressions successfully, our ability to attract potential buyers and sellers and retain and expand business with existing buyers and sellers could be harmed and our business, financial condition and operating results could be adversely affected.

Malfunction or failure of our systems, or other systems that interact with our systems, could disrupt our operations and negatively impact our business and results of operations to a level in excess of any applicable business interruption insurance. Interruption in the operation of our solution would result in a loss of revenue and potential liability to buyers and sellers, and any significant instances of system downtime could negatively affect our reputation and ability to sell our solution.

Any breach of confidential data in our possession could expose us to significant expense and liabilities and harm our reputation.

We must maintain facility and systems security measures to preserve the confidentiality of certain data belonging or related to sellers and buyers and their clients that is transmitted through or stored on our systems or is otherwise in our possession. Additionally, we maintain our own confidential information, and confidential information received from other third parties, in our facilities and systems. We take steps to protect the security, integrity, and confidentiality of this data, but there is no guarantee that inadvertent or unauthorized use or disclosure will not occur or that third parties will not gain unauthorized access to this data despite our efforts. Security breaches, computer malware and computer hacking attacks may occur on our systems or those of our information technology vendors in the future. Any security breach with respect to this information, whether caused by hacking, the inadvertent transmission of computer viruses or other harmful software code, or otherwise, could result in the unauthorized disclosure, misuse, or loss of information, legal claims and litigation, indemnity obligations, regulatory fines and penalties, contractual obligations and liabilities, other liabilities, and significant costs for remediation and re-engineering to prevent future occurrences. In addition, if our security measures or those of our vendors are breached or unauthorized access to consumer data otherwise occurs, our solution may be perceived as not being secure, and sellers and buyers may reduce or cease the use of our solution. Additionally, buyers and sellers typically have security measures in place, but we typically do not have means for controlling the adequacy or efficacy of their security measures.

Despite our security measures, and those of buyers and sellers, we are subject to ongoing threats and, therefore, these security measures may be breached as a result of employee error, failure to implement appropriate processes and procedures, malfeasance, third-party action, including cyber-attacks or other international misconduct by computer hackers or otherwise. This could result in third parties obtaining unauthorized access to sellers’ or advertisers’ data or our data, including personally identifiable information, intellectual property and other confidential business information. Third parties may also attempt to fraudulently induce employees into disclosing sensitive information such as user names, passwords or other information in order to gain access to our advertisers’ data or our data, including intellectual property and other confidential business information.

Because techniques used to obtain unauthorized access or sabotage systems change frequently and generally are not identified until they are launched against a target, we may be unable to anticipate these techniques or to implement adequate preventative or mitigation measures. Though it is difficult to determine what harm may directly result from any specific interruption or breach, any failure to maintain performance, reliability, security and availability of our network infrastructure or otherwise to maintain the confidentiality, security, and integrity of data that we store or otherwise maintain may harm our reputation and our relationships with advertisers and sellers or harm our ability to retain and attract new buyers and sellers. Any of these could harm our business, financial condition and results of operations.

If any such unauthorized disclosure or access does occur, we may be required to notify buyers and sellers or those persons whose information was improperly used, disclosed or accessed. We may also be subject to claims of breach of contract for such use or disclosure, investigation and penalties by regulatory authorities and potential claims by persons whose information was improperly used or disclosed. The unauthorized use or disclosure of information in our control may result in the termination of one or more of our commercial relationships or a reduction in the confidence of buyers, sellers, or Internet users and usage of our solution. We may also be subject to litigation and regulatory action alleging the improper use, transmission or storage of confidential information,

which could damage our reputation among our current and potential buyers, sellers, or Internet users, require significant expenditures of capital and other resources and cause us to lose business and revenue.

Failure to maintain the brand security features of our solution could harm our reputation and expose us to liabilities.

Advertising is bought and sold through our solution in automated transactions that occur in milliseconds. It is important to sellers that the advertising placed on their media be of high quality, consistent with applicable seller standards, not conflict with existing seller arrangements, and compliant with applicable legal and regulatory requirements. It is important to buyers that their advertisements are placed on appropriate media, in proximity with appropriate content, that the impressions for which they are charged are legitimate, and that their advertising campaigns yield their desired results. We use various measures, including proprietary technology, in an effort to store, manage and process rules set by buyers and sellers and to ensure the quality and integrity of the results delivered to sellers and advertisers through our solution. If we fail to properly implement or honor rules established by buyers and sellers, improper advertisements may be placed through our platform, which can result in harm to our reputation as well as the need to pay refunds and other potential legal liabilities.

If we fail to detect fraud or other actions that impact advertisement performance, sellers, advertisers or buyers could lose confidence in our solution, which would cause our business to suffer. If we terminate relationships with sellers as a result of our screening efforts, our volume of paid impressions may decline.

We have in the past, and may in the future, be subject to fraudulent and malicious activities undertaking by persons seeking to use our platform to divert or artificially inflate the purchases by buyers through our platform. Examples of such activities include the use of bots, or other automated or manual mechanisms to generate fraudulent impressions that are delivered through our platform, which could overstate the performance of advertising impressions. We use proprietary technology to identify non-human inventory and traffic. During the year ended December 31, 2013, as a result of our screening and detection efforts, we terminated relationships with over 50 sellers that appeared to be engaging in such activities, resulting in fewer paid impressions in the year than would have otherwise occurred. Because buyers will frequently re-allocate campaigns to other sellers, it is difficult to measure the precise impact on paid impressions and revenue from the loss of these sellers. Although we assess the quality and performance of advertising on sellers’ digital media properties, it may be difficult to detect fraudulent or malicious activity because we do not own content and we rely in part on sellers for controls with respect to such activity. Further, perpetrators of fraudulent impressions change their tactics and may become more sophisticated, requiring us to improve over time our processes for assessing the quality of seller’s inventory and controlling fraudulent activity. If fraudulent or other malicious activity is perpetrated by others, and we fail to detect or prevent it, the affected advertisers may experience or perceive a reduced return on their investment resulting in dissatisfaction with our solution, refusals to pay, refund demands or loss of confidence of buyers or sellers or withdrawal of future business. We could experience similar consequences if inventory sold through our platform is not viewable by the consumer for technical or other reasons.

Any acquisitions we undertake may disrupt our business, adversely affect operations, and dilute stockholders.

Acquisitions have been an important element of our business strategy, and we have completed four acquisitions in the last four years. We may continue to pursue acquisitions in an effort to increase revenue, expand our market position, add to our technological capabilities, respond to dynamic market conditions, or for other strategic or financial purposes. Historically, our acquisitions have been to acquire talent and technological capabilities. In the future, there is no assurance that we will identify suitable acquisition candidates or complete any acquisitions on favorable terms, or at all. Further, any acquisitions we do complete would involve a number of risks, including the following:

If we fail to attract, motivate, train, and retain highly qualified engineering, marketing, sales and management personnel, our ability to execute our business strategy could be impaired.

We rely to a significant degree upon our founder, Chief Executive Officer and Chief Product Architect, Frank Addante; our President, Gregory R. Raifman; and our Chief Operating Officer and Chief Financial Officer, Todd Tappin, for their strategic vision, industry knowledge, management execution, and leadership. The loss of any of them would have a significant adverse effect upon our business.

In addition, our success depends significantly upon our ability to recruit, train, motivate, and retain key technology, engineering, sales and management personnel. We are a technology-driven company and the innovation and delivery of complex solutions at massive scale upon which our success depends are technological and engineering problems. It is imperative that we have highly skilled mathematicians, computer scientists, engineers and engineering management, and appropriately qualified personnel can be difficult to recruit and retain. In addition, as we execute on our international expansion strategy, we will encounter staffing challenges that are unique to a particular country or region, such as recruiting and retaining qualified personnel in foreign countries and difficulty managing such personnel and integrating them into our culture. Skilled and experienced management is critical to our ability to execute against our strategic vision and maintain our performance through the growth and change we anticipate. For certain of our employees, including our CEO, all or a significant portion of their equity ownership is vested. As a result, it may be more difficult, and require additional equity awards, for us to continue to retain and motivate these persons.

Competition for employees with experience in our industry can be intense, particularly in California, New York, and London, where our operations and the operations of other digital media companies are concentrated and where other technology companies compete for management and engineering talent. Other employers may be able to provide better compensation, more diverse opportunities, and better chances for career advancement.

None of our founders or other key employees has an employment agreement for a specific term, and any of our employees may terminate his or her employment with us at any time.

It can be difficult, time-consuming, and expensive to recruit personnel with the combination of skills and attributes required to execute our business strategy, and we may be unable to hire or retain sufficient numbers of qualified individuals in the markets where we do business or plan to do business. New hires require significant training and it may take significant time before they achieve full productivity. As a result, we may incur significant costs to attract and retain employees, including significant expenditures related to salaries and benefits and compensation expenses related to equity awards, and we may lose new employees to our competitors or other companies before we realize the benefit of our investment in recruiting and training. Moreover, new employees may not be or become as productive as we expect, and we may face challenges in adequately or appropriately integrating them into our workforce and culture. In addition, as we move into new geographies, we will need to attract and recruit skilled employees in those areas. We have little experience with recruiting in geographies outside of the United States, and may face additional challenges in attracting, integrating and retaining international employees.

Even if we are successful in hiring qualified new employees, we may be subject to allegations that we have improperly solicited such employees while they remained employed by our competitors, that such employees have improperly solicited other colleagues of theirs employed by the same competitors, or that such employees have divulged proprietary or other confidential information to us in violation of their agreements with such competitors.

Our proprietary rights may be difficult to enforce, which could enable others to copy or use aspects of our solution without compensating us, thereby eroding our competitive advantages and harming our business.

Our success depends, in part, on our ability to protect proprietary methods and technologies that we develop or otherwise acquire, so that we can prevent others from using our inventions and proprietary information. If we fail to protect our intellectual property rights adequately, our competitors might gain access to our technology, and our business might be adversely affected. We rely on trademark, copyright, trade secret laws, confidentiality procedures and contractual provisions to protect our proprietary methods and technologies. Our patent strategy is still in its early stages and, while we have three issued patents, six pending U.S. patent applications and three pending patent applications in other jurisdictions, valid patents may not be issued from our pending applications, and the claims of our issued patents or the claims eventually allowed on any pending applications may not be sufficiently broad to protect our technology or offerings and services. Any issued patents may be challenged, invalidated or circumvented, and any rights granted under these patents may not actually provide adequate defensive protection or competitive advantages to us. Additionally, the process of obtaining patent protection is expensive and time-consuming, and we may not be able to prosecute all necessary or desirable patent applications at a reasonable cost or in a timely manner. Additional uncertainty may result from changes to intellectual property legislation enacted in the United States, including the recent America Invents Act, and other national governments and from interpretations of the intellectual property laws of the United States and other countries by applicable courts and agencies. Accordingly, despite our efforts, we may be unable to obtain adequate patent protection, or to prevent third parties from infringing upon or misappropriating our intellectual property.

Unauthorized parties may attempt to copy aspects of our technology or obtain and use information that we regard as proprietary. We generally enter into confidentiality and/or license agreements with our employees, consultants, vendors and advertisers, and generally limit access to and distribution of our proprietary information. However, we cannot assure you that any steps taken by us will prevent misappropriation of our technology and proprietary information or infringement of our intellectual property rights. Policing unauthorized use of our technology and intellectual property is difficult. Effective trade secret, copyright, trademark, domain name and patent protection are expensive to develop and maintain, both in terms of obtaining and maintaining such rights as well as the costs of defending our rights. We may be required to protect our intellectual property in an

increasing number of jurisdictions, a process that is expensive and may not be successful or which we may not pursue in every location. We may, over time, increase our investment in protecting our intellectual property through additional patent filings which could be expensive and time-consuming. Our competitors and others could attempt to capitalize on our brand recognition by using domain names or business names similar to ours, and we may be unable to prevent third parties from acquiring or using domain names and other trademarks that infringe on, are similar to, or otherwise decrease the value of our brands, trademarks or service marks. In addition, the laws of some foreign countries may not be as protective of intellectual property rights as those of the United States, and mechanisms for enforcement of our proprietary rights in such countries may be inadequate. Also, despite the steps we have taken to protect our proprietary rights, it may be possible for unauthorized third parties to copy or reverse engineer aspects of our technology or otherwise obtain and use information that we regard as proprietary, or to develop technologies similar or superior to our technology or design around our proprietary rights.

From time to time, legal action by us may be necessary or appropriate to enforce our intellectual property rights, to protect our trade secrets, to determine the validity and scope of the proprietary rights of others, or to defend against claims of infringement. Such litigation could result in substantial costs and the diversion of limited resources and could negatively affect our business, operating results and financial condition. If we are unable to protect our proprietary rights (including aspects of our technology solution) we may find ourselves at a competitive disadvantage to others who have not incurred the same level of expense, time and effort to create and protect their technology and intellectual property.

We may be subject to intellectual property rights claims by third parties, which are costly to defend, could require us to pay significant damages and could limit our ability to use certain technologies and intellectual property.

The digital advertising industry is characterized by the existence of large numbers of patents, copyrights, trademarks, trade secrets and other intellectual property and proprietary rights. Companies in this industry are often required to defend against litigation claims that are based on allegations of infringement or other violations of intellectual property rights. Our technologies may not be able to withstand any third-party claims or rights against their use.

Third parties may assert claims of infringement or misappropriation of intellectual property rights in proprietary technology against us or against buyers for which we may be liable or have an indemnification obligation. We cannot assure you that we are not infringing or violating any third-party intellectual property rights. From time to time, we or buyers and sellers may be subject to legal proceedings relating to our solution or underlying technology and the intellectual property rights of others, particularly as we expand the complexity and scope of our business. As a result of disclosure of information in filings required of a public company, our business and financial condition will become more visible, which may result in threatened or actual litigation, including by competitors and other third parties.

Regardless of whether claims that we are infringing patents or infringing or misappropriating other intellectual property rights have any merit, these claims are time-consuming and costly to evaluate and defend, and can impose a significant burden on management and employees. The outcome of any litigation is inherently uncertain, and we may receive unfavorable interim or preliminary rulings in the course of litigation. There can be no assurances that favorable final outcomes will be obtained in all cases. We may decide to settle lawsuits and disputes on terms that are unfavorable to us. Some of our competitors have substantially greater resources than we do and are able to sustain the costs of complex intellectual property litigation to a greater degree and for longer periods of time than we could.

Although third parties may offer a license to their technology or intellectual property, the terms of any offered license may not be acceptable and the failure to obtain a license or the costs associated with any license could cause our business, results of operations or financial condition to be materially and adversely affected. In

addition, some licenses may be non-exclusive, and therefore our competitors may have access to the same technology or intellectual property licensed to us. Alternatively, we may be required to develop non-infringing technology or to make other changes, such as to our branding, which could require significant effort and expense and ultimately may not be successful. Furthermore, a successful claimant could secure a judgment or we may agree to a settlement that prevents us from distributing certain products or performing certain services or that requires us to pay substantial damages, including treble damages if we are found to have willfully infringed such claimant’s patents or copyrights, royalties or other fees. Claims of intellectual property infringement or misappropriation also could result in injunctive relief against us, or otherwise result in delays or stoppages in providing all or certain aspects of our solution. Any of the foregoing could adversely affect our relationships with current or future buyers and sellers.

We are subject to government regulations concerning our employees, including wage-hour laws and taxes.

We are subject to applicable rules and regulations relating to our relationship with our employees, including health benefits, unemployment and similar taxes, overtime and working conditions, immigration status and classification of employee benefits for tax purposes. Legislated increases in additional labor cost components, such as employee benefit costs, workers’ compensation insurance rates, compliance costs and fines, as well as the cost of litigation in connection with these regulations, would increase our labor costs. Moreover, we are subject to various laws and regulations in federal, state and foreign jurisdictions that impose varying rules and obligations on us with respect to the classification of employee benefits for income tax and other purposes and that require us to report and/or withhold in respect of such items. In addition, many employers nationally have been subject to actions brought by governmental agencies and private individuals under wage-hour laws on a variety of claims, such as improper classification of workers as exempt from overtime pay requirements and failure to pay overtime wages properly, with such actions sometimes brought as class actions, and these actions can result in material liabilities and expenses. Should we be subject to employment litigation, such as actions involving wage-hour, overtime, break and working time, it may distract our management from business matters and result in increased labor costs.

Our international operations and expansion plans require increased expenditures and impose additional risks and compliance imperatives, and failure successfully to execute our international plans will adversely affect our growth and operating results.

We have numerous operations outside of the United Sates, and we expect our international operations to contribute significantly to our future growth. While we currently conduct business in Northern Europe, Australia and Japan, our expansion plans are also focused on the rest of Asia, Brazil and other Latin American countries, and other countries in Europe. However, our experience operating outside the United States is still limited, and our international employees currently represent a modest portion of our headcount. Achievement of our international objectives will require a significant amount of attention from our management, finance, analytics, operations, sales and engineering teams, as well as significant investment in developing the technology infrastructure necessary to deliver our solution and establishing sales, delivery, support, and administrative capabilities in the countries where we operate. Attracting new buyers and sellers outside the United States may require more time and expense than in the United States, in part due to the need to educate such buyers and sellers about our solution, and we may not be successful in establishing and maintaining these relationships. In addition, our international operations will require us to develop and administer our internal controls and legal and compliance practices in countries with different cultural norms and different business practices than the United States.

International operations also impose risks and challenges in addition to those faced in the United States, including management of a distributed workforce; the need to adapt our offering to satisfy local requirements and standards; laws and business practices that may favor local competitors; longer accounts receivable payment

cycles and other collection difficulties; the effect of global and regional recessions and economic and political instability; potentially adverse tax consequences in the United States and abroad; staffing challenges, including difficulty in recruiting and retaining qualified personnel as well as managing such a diversity in personnel; reduced or ineffective protection of our intellectual property rights in some countries; and costs and restrictions affecting the repatriation of funds to the United States.

One or more of these requirements and risks may make our international operations more difficult and expensive or less successful than we expect, and may preclude us from operating in some markets. There is no assurance that our international expansion efforts will be successful, and we may not generate sufficient revenue or margins from international business to cover our expenses or contribute to growth.

Operating in multiple countries requires us to comply with different legal and regulatory requirements.

Our international operations subject us to laws and regulations of multiple jurisdictions, as well as U.S. laws governing international operations. These various laws and regulations are often evolving and sometimes conflict. For example, the Foreign Corrupt Practices Act, or FCPA, and comparable foreign laws and regulations (including the U.K. Bribery Act) prohibit improper payments or offers of payments to foreign governments and their officials and political parties by U.S. and other business entities for the purpose of obtaining or retaining business. Other laws and regulations prohibit bribery of private parties and other forms of corruption. As we expand our international operations, there is some risk of unauthorized payment or offers of payment or other inappropriate conduct by one of our employees, consultants, agents or other contractors, which could constitute a violation of by us various laws including the FCPA, even though such parties are not always subject to our control. Safeguards we implement to discourage these practices may prove to be less than effective and violations of the FCPA and other laws may result in severe criminal or civil sanctions, or other liabilities or proceedings against us, including class action law suits and enforcement actions from the SEC, Department of Justice and international regulators. Other laws applicable to our international business include local employment, tax, privacy, data security, and intellectual property protection laws and regulations. In some cases, buyers and sellers operating in non-U.S. markets may impose additional requirements on our non-U.S. business in efforts to comply with their interpretation of their own or our legal obligations. These requirements may differ significantly from the requirements applicable to our business in the United States and may require engineering and other costly resources to accommodate. As these laws continue to evolve and we expand to more jurisdictions, compliance will become more complex and expensive, and the risk of non-compliance will increase.

Compliance with complex foreign and U.S. laws and regulations that apply to our international operations increases our cost of doing business abroad, and violation of these laws or regulations may interfere with our ability to offer our solution competitively in one or more countries, expose us or our employees to fines and penalties, and result in the limitation or prohibition of our conduct of business.

We are subject to governmental export and import controls that could subject us to liability or impair our ability to compete in international markets.

Our operations are subject to U.S. export controls, specifically the Export Administration Regulations, or EAR, and economic sanctions enforced by the Office of Foreign Assets Control. These regulations provide that encryption technology may be exported outside of the United States only with the required export authorizations, including by license, license exception or other appropriate government authorizations, which may require the filing of an encryption registration and classification request. Furthermore, U.S. export control laws and economic sanctions prohibit the shipment of certain products and services to countries, governments, and persons targeted by U.S. sanctions. We incorporate encryption technology into the servers that operate our solution. As a result of locating some servers in data centers outside of the United States, we may have exported encryption technology prior to obtaining the required export authorizations and/or submitting the required requests, including a classification request and/or request for an encryption registration number, resulting in a possible

inadvertent violation of U.S. export control laws. As a result, in January 2014, we filed a Voluntary Self Disclosure with the U.S. Department of Commerce’s Bureau of Industry and Security, or BIS, concerning these potential violations. While the potential penalties for violations of the EAR include a monetary fine of up to $250,000 or twice the value of the transaction, whichever is greater, per violation and/or a denial of export privileges under the EAR, we do not expect a penalty to be assessed against us in connection with our Voluntary Self Disclosure and, if one is assessed, we do not expect it to be material.

In addition, various countries regulate the import of certain encryption technology, including through import permit and license requirements, and have enacted laws that could limit our ability to deploy our technology or could limit our customers’ ability to use our solution in those countries. Changes in our technology or changes in export and import regulations may create delays in the introduction of our solution or the deployment of our technology in international markets, prevent our customers with international operations from using our solution globally or, in some cases, prevent the export or import of our technology to certain countries, governments or persons altogether. Any change in export or import regulations, economic sanctions or related legislation, shift in the enforcement or scope of existing regulations, or change in the countries, governments, persons or technologies targeted by such regulations, could result in decreased use of our solution by, or in our decreased ability to export our technology to, international markets. Any decreased use of our solution or limitation on our ability to export our technology or sell our solution would likely adversely affect our business, financial condition and results of operations.

Fluctuations in the exchange rates of foreign currencies could result in currency transaction losses that negatively impact our financial results.

We currently have transactions denominated in U.S. Dollars, British Pounds, Euros, Australian Dollars, Swedish Kronas, Danish Krones, Norwegian Krones, Brazilian Reals and Japanese Yen and may, in the future, have sales denominated in the currencies of additional countries in which we establish or have established sales offices. In addition, we incur a portion of our expenses in many of these same currencies, as well as other currencies, and to the extent we need to convert U.S. Dollars or a different foreign currency to pay expenses, we are exposed to unfavorable changes in exchange rates and added transaction costs. We expect international sales and transactions to become an increasingly important part of our business. Such sales and transactions may be subject to unexpected regulatory requirements and other barriers. Any fluctuation in the exchange rates of these foreign currencies may negatively impact our business, financial condition and results of operations. We have not previously engaged in foreign currency hedging. If we decide to hedge our foreign currency exposure, we may not be able to hedge effectively due to lack of experience, unreasonable costs or illiquid markets. In addition, those activities may be limited in the protection they provide us from foreign currency fluctuations and can themselves result in losses.

We have identified certain material weaknesses in our internal control over financial reporting. Failure to maintain effective internal controls could cause our investors to lose confidence in us and adversely affect the market price of our common stock. If our internal controls are not effective, we may not be able to accurately report our financial results or prevent fraud.

Section 404 of the Sarbanes-Oxley Act of 2002, or Section 404, requires that we maintain internal control over financial reporting that meets applicable standards. We may err in the design or operation of our controls, and all internal control systems, no matter how well designed and operated, can provide only reasonable assurance that the objectives of the control system are met. Because there are inherent limitations in all control systems, there can be no absolute assurance that all control issues have been or will be detected. If we are unable, or are perceived as unable, to produce reliable financial reports due to internal control deficiencies, investors could lose confidence in our reported financial information and operating results, which could result in a negative market reaction.

Following our initial public offering, we will be required, pursuant to Section 404, to furnish a report by management on, among other things, the effectiveness of our internal control over financial reporting. We will need to disclose any material weaknesses identified by our management in our internal control over financial reporting, and, when we are no longer an “emerging growth company,” we will need to provide a statement that our independent registered public accounting firm has issued an opinion on our internal control over financial reporting, provided that our independent registered public accounting firm will not be required to attest to the effectiveness of our internal control over financial reporting until our first annual report required to be filed with the Securities and Exchange Commission, or SEC, following the later of the date we are deemed to be an “accelerated filer” or a “large accelerated filer,” each as defined in the Securities Exchange Act of 1934, as amended, or the Exchange Act, or the date we are no longer an “emerging growth company,” as defined in the Jumpstart Our Businesses Act of 2012, or the JOBS Act.

We have identified certain material weaknesses in our internal controls resulting from:

While we have designed and implemented, or expect to implement, measures that we believe address these control weaknesses, we continue to develop our internal controls, processes and reporting systems by, among other things, hiring qualified personnel with expertise to perform specific functions, implementing software systems to manage our revenue and expenses and to allow us to budget, undertaking multi-year financial planning and analyses and designing and implementing improved processes and internal controls, including ongoing senior management review and audit committee oversight. We commenced measures to remediate the identified material weaknesses during the third quarter of 2013 and expect that such remediation will be completed by the end of 2014. We have incurred significant costs to remediate these weaknesses, primarily personnel costs, external consulting fees, system implementation costs, and related indirect costs including the use of facilities and technology, and we expect to incur additional costs to remediate these weaknesses. Because some of the personnel costs and systems resources also support our general operations and the scale and growth of our business, we cannot precisely separate costs related to our material weakness remediation from costs associated with our overall internal control efforts. However, we estimate that the incremental costs of our internal audit employees and external consultants who are primarily focused on material weakness remediation and internal control testing were approximately $0.3 million for the year ended December 31, 2013. We expect such costs will approximate $0.9 million for the year ended December 31, 2014. We may not be successful in implementing these systems or in developing other internal controls, which may undermine our ability to provide accurate, timely and reliable reports on our financial and operating results. Further, we will not be able to fully assess whether the steps we are taking will remediate the material weaknesses in our internal control over financial reporting until we have completed our implementation efforts and sufficient time passes in order to evaluate their effectiveness. In addition, if we identify additional errors that result in material weaknesses in our internal control over financial reporting, we may not detect errors on a timely basis and our financial statements may be materially misstated. Moreover, in the future we may engage in business transactions, such as acquisitions, reorganizations or implementation of new information systems that could negatively affect our internal control over financial reporting and result in material weaknesses.

If we identify new material weaknesses in our internal control over financial reporting, if we are unable to comply with the requirements of Section 404 in a timely manner, if we are unable to assert that our internal control over financial reporting is effective, or if our independent registered public accounting firm is unable to express an opinion as to the effectiveness of our internal control over financial reporting, we may be late with the filing of our periodic reports, investors may lose confidence in the accuracy and completeness of our financial reports and the market price of our common stock could be negatively affected. As a result of such failures, we could also become subject to investigations by the stock exchange on which our securities are listed, the SEC, or other regulatory authorities, and become subject to litigation from investors and stockholders, which could harm our reputation, financial condition or divert financial and management resources from our core business.

A portion of our assets consists of capitalized software development costs, goodwill and other intangible assets acquired in connection with acquisitions. Current accounting standards require us to evaluate goodwill on an annual basis and other intangibles if certain triggering events occur, and adjust the carrying value of these assets to net realizable value when such testing reveals impairment of the assets. Various factors, including regulatory or competitive changes, could affect the value of our intangible assets. If we are required to write-down the value of our goodwill or intangible assets due to impairment, our reported expenses will increase, resulting in a corresponding decrease in our reported profit.

If our estimates or judgments relating to our critical accounting policies are erroneous or based on assumptions that change or prove to be incorrect, our operating results could fall below the expectations of securities analysts and investors, resulting in a decline in our stock price.

The preparation of financial statements in conformity with generally accepted accounting principles in the United States, or GAAP, requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. We base our estimates on our best judgment, historical experience, information derived from third parties, and on various other assumptions that we believe to be reasonable under the circumstances, as provided in the section entitled “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” the results of which form the basis for making judgments about the carrying values of assets, liabilities, equity, revenue and expenses that are not readily apparent from other sources. Our operating results may be adversely affected if our judgments prove to be wrong, assumptions change or actual circumstances differ from those in our assumptions, which could cause our operating results to fall below the expectations of securities analysts and investors, resulting in a decline in our stock price. Significant assumptions and estimates used in preparing our consolidated financial statements include those related to revenue recognition, stock-based compensation and income taxes.

We report revenue on a net basis. If, in the future, we engage in transactions for which revenue is recorded on a gross basis, we may have significant increases in our revenue and decreases in our GAAP margins that do not necessarily correspond with changes in our underlying business, which could cause comparisons with prior periods to be less meaningful and make it more difficult for investors to evaluate our performance.

The recognition of our revenue is governed by certain criteria that must be met and that determine whether we report revenue either on a gross basis, as a principal, or net basis, as an agent, depending upon the nature of the sales transaction. Our revenue is currently recognized on a net basis. In the future we may engage in transactions for which revenue is recorded on a gross basis, due to substantive changes in our business, such as through acquisitions, changes to the commercial terms with buyers and sellers or structural changes to our existing business. In the latter case, we may have significant increases in our revenue and decreases in our GAAP margins that do not necessarily correspond with changes in our underlying activity. We may experience significant fluctuations in revenue and margins in future periods depending upon, in part, the nature of our sales and our recognition of such revenue.

The U.S. and non-U.S. tax laws applicable to our business activities are subject to interpretation. We are subject to audit by the Internal Revenue Service and by taxing authorities of the state, local and foreign jurisdictions in which we operate. Our tax obligations are based in part on our corporate operating structure, including the manner in which we develop, value, and use our intellectual property and sell our solutions, the jurisdictions in which we operate, how tax authorities assess revenue based taxes such as sales and use taxes, the scope of our international operations and the value we ascribe to our intercompany transactions. Taxing authorities may challenge our tax positions and methodologies for valuing developed technology or intercompany arrangements, as well as our positions regarding jurisdictions in which we are subject to certain taxes, which could expose us to additional taxes and increase our worldwide effective tax rate. Any adverse outcomes of such challenges to our tax positions could result in additional taxes for prior periods, interest, and penalties as well as higher future taxes. In addition, our future tax expense could increase as a result of changes in tax laws, regulations or accounting principles, or as a result of earning income in jurisdictions that have higher tax rates. An increase in our tax expense could have a negative effect on our financial position and results of operations. Moreover, the determination of our provision for income taxes and other tax liabilities requires significant estimates and judgment by management, and the tax treatment of certain transactions is uncertain. Although we believe we will make reasonable estimates and judgments, the ultimate outcome of any particular issue may differ from the amounts previously recorded in our financial statements and any such occurrence could materially affect our financial position and results of operations.

Our ability to use our net operating losses and tax credit carryforwards to offset future taxable income may be subject to certain limitations which could result in higher tax liabilities.

The ability to fully utilize our net operating loss and tax credit carryforwards to offset future taxable income may be limited. At December 31, 2013, we had U.S. federal net operating loss carryforwards, or NOLs, of approximately $36.7 million, state NOLs of approximately $43.3 million, federal research and development tax credit carryforwards, or credit carryforwards, of approximately $3.0 million, and state credit carryforwards of approximately $2.4 million. A lack of future taxable income would adversely affect our ability to utilize these NOLs and credit carryforwards. In addition, under Section 382 and 383 of the Internal Revenue Code of 1986, as amended, or the Code, and comparable state income tax laws, a corporation that undergoes an “ownership change” is subject to limitations on its ability to utilize its NOLs and credit carryforwards to offset future taxable income following the ownership change. As a result, future changes in our stock ownership, including this or future offerings, as well as other direct or indirect changes in our ownership that may be outside of our control, could result in limitations on our ability to fully utilize our NOLs and credit carryforwards. The Company had an ownership change in January 2008 and $2.3 million of federal and state NOLs are already subject to limitation under Section 382. Additionally, approximately $3.4 million of our federal NOLs and approximately $3.4 million of our state NOLs were generated by corporations that we acquired during the pre-acquisition period, and thus those NOLs already are subject to limitation under Section 382 of the Code and comparable state income tax laws. In addition, depending on the level of our taxable income, all or a portion of our NOLs and credit carryforwards may expire unutilized, which could prevent us from offsetting future taxable income by the entire amount of our current and future NOLs and credit carryforwards. We have recorded a full valuation allowance related to our NOLs, credit carryforwards and other net deferred tax assets due to the uncertainty of the ultimate realization of the future benefits of those assets. To the extent we determine that all, or a portion of, our valuation allowance is no longer necessary, we will reverse the valuation allowance and recognize income tax benefit in the reported financial statement earnings in that period. Once the valuation allowance is eliminated or reduced, its reversal will no longer be available to offset our current financial statement tax provision in future periods.

We may require additional capital to support growth, and such capital might not be available on terms acceptable to us, if at all. Inability to obtain financing could limit our ability to conduct necessary operating activities and make strategic investments.

We intend to continue to make investments in pursuit of our strategic objectives and to support our business growth. Various business challenges may require additional funds, including the need to respond to competitive

threats or market evolution by developing new solutions and improving our operating infrastructure, either through additional hiring or acquisition of complementary businesses or technologies, or both. In addition, we could incur significant expenses or shortfalls in anticipated cash generated as a result of unanticipated events in our business or competitive, regulatory, or other changes in our market.

Our available cash and cash equivalents including the net proceeds of this offering, the cash we anticipate generating from operations, and our available line of credit under our credit facility may not be adequate to meet our capital needs, and therefore we may need to engage in equity or debt financings to secure additional funds. We may not be able to obtain additional financing on terms favorable to us, if at all. If we are unable to obtain adequate financing on terms satisfactory to us when we require it, our ability to continue to support our business growth and respond to business challenges could be significantly impaired, and our business may be adversely affected.

If we do raise additional funds through future issuances of equity or convertible debt securities, our existing stockholders could suffer significant dilution, and any new equity securities we issue could have rights, preferences and privileges superior to those of holders of our common stock. Any debt financing that we secure in the future could involve restrictive covenants relating to our capital raising activities and other financial and operational matters, including the ability to pay dividends. This may make it more difficult for us to obtain additional capital and to pursue business opportunities, including potential acquisitions. In addition, if we issue debt, the holders of that debt would have prior claims on the company’s assets, and in case of insolvency, the claims of creditors would be satisfied before distribution of value to equity holders, which would result in significant reduction or total loss of the value of our equity.

Our credit facility subjects us to operating restrictions and financial covenants that impose risk of default and may restrict our business and financing activities.

On September 27, 2011, we entered into a loan and security agreement with Silicon Valley Bank that, as amended to date, provides a senior secured revolving credit facility in the aggregate principal amount of $40 million. As of December 31, 2013, we had $3.8 million outstanding under this loan and security agreement. Borrowings under this agreement are secured by substantially all of our tangible personal property assets and all of our intangible assets are subject to a negative pledge in favor of Silicon Valley Bank. This credit facility is subject to certain financial ratio and liquidity covenants, as well as restrictions that limit our ability, among other things, to:

These covenants may restrict our ability to finance our operations and to pursue our business activities and strategies. Our ability to comply with these covenants may be affected by events beyond our control. In the past, we were not compliant with certain administrative covenants. Although the bank waived such noncompliance or agreed to amend certain covenants in the past, there is no guarantee it will do so in the future. If a default were to occur and is not waived, such default could cause, among other remedies, all of the outstanding indebtedness

under our loan and security agreement to become immediately due and payable. In such an event, our liquid assets might not be sufficient to meet our repayment obligations, and we might be forced to liquidate collateral assets at unfavorable prices or our assets may be foreclosed upon and sold at unfavorable valuations.

Our ability to renew our existing credit facility, which matures in September 2018, or to enter into a new credit facility to replace or supplement the existing facility may be limited due to various factors, including the status of our business, global credit market conditions, and perceptions of our business or industry by sources of financing. In addition, if credit is available, lenders may seek more restrictive covenants and higher interest rates that may reduce our borrowing capacity, increase our costs, and reduce our operating flexibility.

If we do not have or are unable to generate sufficient cash available to repay our debt obligations when they become due and payable, either upon maturity or in the event of a default, we may not be able to obtain additional debt or equity financing on favorable terms, if at all. Our inability to obtain financing may negatively impact our ability to operate and continue our business as a going concern.

Risks Related to this Offering, the Securities Markets and Ownership of our Common Stock

The price of our common stock may be volatile and the value of your investment could decline.

Technology stocks have historically experienced high levels of volatility. The trading price of our common stock following this offering may fluctuate substantially. Following the completion of this offering, the market price of our common stock may be higher or lower than the price you pay in the offering, depending on many factors, some of which are beyond our control and may not be related to our operating performance. These fluctuations could cause you to lose all or part of your investment in our common stock. Factors that could cause fluctuations in the trading price of our common stock include the following:

In addition, if the market for technology stocks or the stock market, in general, experiences a loss of investor confidence, the trading price of our common stock could decline for reasons unrelated to our business,

results of operations or financial condition. The trading price of our common stock might also decline in reaction to events that affect other companies in our industry even if these events do not directly affect us. In the past volatility in the market price of a company’s securities has often resulted in securities class action litigation been brought against that company. If our stock price is volatile, we may become the target of securities litigation, which would result in substantial costs and divert our management’s attention and resources from our business.

Sales of substantial amounts of our common stock in the public markets, including when the “lock-up” or “market standoff” period ends, or the perception that sales might occur, could reduce the price of our common stock and may dilute your voting power and your ownership interest in us.

Sales of a substantial number of shares of our common stock in the public market after this offering, or the perception that these sales could occur, could adversely affect the market price of our common stock and may make it more difficult for you to sell your common stock at a time and price that you deem appropriate. Based on the total number of outstanding shares of our common stock as of March 18, 2014, upon completion of this offering, we will have 34,715,103 shares of common stock outstanding, excluding shares of common stock issuable upon exercise of outstanding stock options and a warrant to purchase 12,587 shares of our common stock. All of the shares of common stock sold in this offering will be freely tradable without restrictions or further registration under the Securities Act of 1933, as amended, or the Securities Act, except for any shares held by our “affiliates” as defined in Rule 144 under the Securities Act.

Subject to certain exceptions described under the caption “Underwriting,” all of our directors and officers and substantially all of our stockholders have agreed not to offer, sell or agree to sell, directly or indirectly, any shares of common stock without the permission of the representatives of the underwriters for a period of 180 days from the date of this prospectus. When the lockup period expires, our locked-up security holders will be able to sell shares in the public market. In addition, the underwriters may, in their sole discretion, release all or some portion of the shares subject to lock-up agreements prior to the expiration of the lock-up period. For certain of our employees, a substantial portion of their equity is vested and eligible for sale upon expiration of the lock-up arrangements. See the section of this prospectus entitled “Shares Eligible for Future Sale” for more information. Sales of a substantial number of such shares upon expiration, or the perception that such sales may occur, or early release of the lock-up, could cause our share price to fall or make it more difficult for you to sell your common stock at a time and price that you deem appropriate.

In addition, promptly following the completion of this offering, we intend to file one or more registration statements on Form S-8 registering the issuance of approximately 10,709,284 million shares of common stock subject to options or other equity awards issued or reserved for issuance under our equity incentive plans. We also intend to register the offer and sale of all other shares of common stock that may be authorized under our current or future equity compensation plans. Shares registered under these registration statements on Form S-8 will be available for sale in the public market subject to vesting arrangements and exercise of options, the lock-up agreements described above and the restrictions of Rule 144 in the case of our affiliates.

Based on shares outstanding as of March 18, 2014, holders of up to approximately 18,119,158 shares, or 52.2%, of our common stock after giving effect to this offering, will have rights, subject to some conditions, to require us to file registration statements covering the sale of their shares or to include their shares in registration statements that we may file for ourselves or other stockholders.

We may issue our shares of common stock or securities convertible into our common stock from time to time in connection with financings, acquisitions, investments or otherwise. Any such issuance could result in substantial dilution to our existing stockholders and cause the trading price of our common stock to decline.

Insiders will continue to have substantial control over us after this offering, which could limit your ability to influence the outcome of key transactions, including a change of control.

Our directors, executive officers and each of our stockholders who own greater than 5% of our outstanding common stock, in the aggregate, will beneficially own approximately 57.2% of the outstanding shares of our common stock after this offering, based on the number of shares outstanding as of March 18, 2014. As a result, these stockholders will be able to influence or control matters requiring approval by our stockholders, including the election of directors and the approval of mergers, acquisitions or other extraordinary transactions. They may also have interests that differ from yours and may vote in a manner that is adverse to your interests. This concentration of ownership may have the effect of deterring, delaying or preventing a change of control of our company, could deprive our stockholders of an opportunity to receive a premium for their common stock as part of a sale of our company, and might ultimately affect the market price of our common stock.

There is no assurance that a market will develop for our common stock or what the market price of our common stock will be.

We cannot assure you that an active trading market for our common stock will develop or, if developed, that any market will be sustained. We cannot predict the prices at which our common stock will trade. The initial public offering price of our common stock was determined by negotiations with the underwriters and may not bear any relationship to the market price at which our common stock will trade after this offering or to any other established criteria of the value of our business.

Our business could be negatively affected as a result of actions of activist stockholders.

Campaigns by stockholders to effect changes at publicly traded companies are sometimes led by investors seeking to increase short-term stockholder value through actions such as financial restructuring, increased debt, special dividends, stock repurchases or sales of assets or the entire company. If we become engaged in a proxy contest with an activist stockholder in the future, our business could be adversely affected as such contests could be costly and time-consuming, disrupt our operations and divert the attention of management and our employees from executing our strategic plan. Additionally, perceived uncertainties as to our future direction as a result of stockholder activism or changes to the composition of our board of directors may lead to the perception of a change in the direction of our business, instability or lack of continuity which may be exploited by our competitors, cause concern to current or potential buyers and sellers on our platform, and make it more difficult to attract and retain qualified personnel. If buyers and/or sellers choose to delay, defer or reduce transactions with us or through our platform or transact with our competitors instead of us because of any such issues, then our revenue, earnings and operating cash flows could be adversely affected.

We have broad discretion in the use of net proceeds that we receive in this offering, and if we do not use those proceeds effectively, your investment could be harmed.

The principal purposes of this offering are to create a public market for our common stock, obtain additional capital, and facilitate our future access to the public equity markets, as well as to increase market awareness of our company and our standing among buyers and sellers and improve our competitive position. We have not yet determined the specific allocation of the net proceeds that we receive in this offering. We intend to use the net proceeds from this offering for general corporate purposes, including working capital, sales and marketing activities, engineering initiatives, including enhancement of our solution and investment in technology and development, general and administrative expenses and capital expenditures. We also may use a portion of the net proceeds from this offering to acquire or invest in technologies, solutions or businesses that complement our business, although we have no present commitments to complete any such transactions. Our management will have broad discretion over the specific use of the net proceeds that we receive in this offering and we have not yet determined how these proceeds will be used, so investors in this offering will need to rely upon the judgment of our management with respect to the use of proceeds. If we do not use the net proceeds that we receive in this offering effectively, we might not be able to obtain a significant return, if any, on investment of these net proceeds.

The requirements of being a public company may strain our resources, divert our management’s attention and affect our ability to attract and retain qualified board members.

As a public company, we will be subject to the reporting requirements of the Exchange Act, and will be required to comply with the applicable requirements of the Sarbanes-Oxley Act and the Dodd-Frank Wall Street Reform and Consumer Protection Act, the listing requirements of the New York Stock Exchange, and other applicable securities rules and regulations. Among other things, we must file annual, quarterly and current reports with respect to our business and results of operations, maintain effective disclosure controls and procedures and internal control over financial reporting, and comply with various requirements regarding the composition and operation of our board of directors. Compliance with these rules and regulations will require significant resources and management oversight, increase our legal and financial compliance costs, make some activities more difficult, time-consuming or costly and increase demand on our systems and resources. As a result, management’s attention and company resources may be diverted from other business concerns. Although we have already hired additional employees to help us comply with these requirements, we may need to hire even more employees in the future, which would increase our costs and expenses.

We also expect that the risks and costs associated with being a public company and complying with related rules and regulations will make it more expensive for us to obtain director and officer liability insurance, and we may be required to accept reduced coverage or incur substantially higher costs to obtain coverage. These factors could also make it more difficult and expensive for us to attract and retain qualified members of our board of directors, particularly to serve on our Audit Committee and Compensation Committee, and qualified executive officers.

We are an “emerging growth company,” and we cannot be certain if the reduced disclosure requirements applicable to emerging growth companies will make our common stock less attractive to investors.

For as long as we remain an “emerging growth company” as defined in the JOBS Act, we may take advantage of certain exemptions from various requirements that are applicable to public companies that are not “emerging growth companies.” For example, we are not required to comply with the independent auditor attestation requirements of Section 404, we may provide reduced disclosure regarding executive compensation in this prospectus and in our periodic reports and proxy statements, and we are exempt from the requirements of holding a nonbinding advisory vote on executive compensation and stockholder approval of any golden parachute payments not previously approved. We may take advantage of these exemptions for so long as we are an “emerging growth company,” which could be as long as five years following the completion of this offering, although, if we have more than $1.0 billion in annual revenue, if the market value of our common stock that is held by non-affiliates exceeds $700 million as of June 30 of any year, or we issue more than $1.0 billion of non-convertible debt over a three-year period before the end of that five-year period, we would cease to be an “emerging growth company” as of the following December 31. Investors may find our common stock less attractive because we rely on these exemptions, which could contribute to a less active trading market for our common stock, and increased volatility or reduction in our stock price.

In addition, the JOBS Act also provides that an “emerging growth company” can take advantage of an extended transition period for complying with new or revised accounting standards. However, we have chosen to “opt out” of such extended transition period, and as a result, we will comply with new or revised accounting standards on the relevant dates on which adoption of such standards is required for non-emerging growth companies. Our decision to opt out of the extended transition period for complying with new or revised accounting standards is irrevocable.

Because the initial public offering price of our common stock is substantially higher than the pro forma net tangible book value per share of our outstanding common stock following this offering, new investors will experience immediate and substantial dilution.

The initial public offering price of our common stock is substantially higher than the pro forma net tangible book value per share of our common stock immediately following this offering based on the total value

of our tangible assets less our total liabilities. Therefore, if you purchase shares of our common stock in this offering, you will experience immediate dilution of $12.13 per share, the difference between the price per share you pay for our common stock and the pro forma net tangible book value per share of our common stock as of December 31, 2013, after giving effect to the issuance of shares of our common stock in this offering. See the section entitled “Dilution.”

If securities or industry analysts do not publish research or reports about our business, or publish inaccurate or unfavorable research reports about our business, our share price and trading volume could decline.

The trading market for our common stock will, to some extent, depend on the research and reports that securities or industry analysts publish about us or our business. We do not have any control over these analysts. If one or more of the analysts who cover us downgrades our shares or changes their opinion of our business prospects, our share price could decline. If one or more of these analysts decreases or ceases coverage of our company, we could lose visibility in the financial markets, which could cause our share price or trading volume to decline.

We do not intend to pay dividends for the foreseeable future and, consequently, your ability to achieve a return on your investment will depend on appreciation in the price of our common stock.

We have never declared or paid any dividends on our common stock. We intend to retain any earnings to finance the operation and expansion of our business, and we do not anticipate paying any cash dividends in the future. As a result, you may only receive a return on your investment in our common stock if the market price of our common stock increases. In addition, our credit facility contains restrictions on our ability to pay dividends.

Provisions of our charter documents and Delaware law may inhibit potential acquisition of the company and limit the ability of stockholders to cause changes in company management.

Our amended and restated certificate of incorporation and amended and restated bylaws, as in effect upon completion of this offering, include provisions, as described below, that could delay or prevent a change in control of the company, and make it difficult for stockholders to elect directors who are not nominated by the current members of our board of directors or take other actions to change company management.

We are also subject to Section 203 of the Delaware General Corporation Law, or the DGCL, which prohibits us from engaging in any business combination with an interested stockholder for a period of three years from the date the person became an interested stockholder, unless certain conditions are met. These provisions make it more difficult for stockholders or potential acquirers to acquire the company without negotiation and may apply even if some of our stockholders consider the proposed transaction beneficial to them. For example, these provisions might discourage a potential acquisition proposal or tender offer, even if the acquisition proposal or tender offer were to be at a premium over the then current market price for our common stock. These provisions could also limit the price that investors are willing to pay in the future for shares of our common stock.

This prospectus contains forward-looking statements that involve risks and uncertainties. The forward-looking statements are contained principally in “Prospectus Summary,” “Risk Factors,” “Use of Proceeds,” “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and “Business.” In some cases, you can identify forward-looking statements by terms such as “may,” “might,” “will,” “objective,” “intend,” “should,” “could,” “can,” “would,” “expect,” “believe,” “design,” “estimate,” “predict,” “potential,” “plan” or the negative of these terms, and similar expressions. These statements reflect our current views with respect to future events and are based on assumptions and subject to known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from current expectations. These risks include, but are not limited to:

We discuss many of these risks in this prospectus in greater detail under the heading “Risk Factors.” Also, these forward-looking statements represent our estimates and assumptions only as of the date of this prospectus. Unless required by federal securities laws, we do not intend to update any of these forward-looking statements to reflect circumstances or events that occur after the statements are made. Given these uncertainties, you should not place undue reliance on these forward-looking statements.

You should read this prospectus and the documents that we reference in this prospectus and have filed as exhibits to the registration statement, of which this prospectus is a part, completely and with the understanding that our actual future results may be materially different from what we expect. We qualify all of our forward-looking statements by these cautionary statements.

Unless otherwise indicated, information contained in this prospectus concerning our industry and the markets in which we operate, including our general expectations and market position, market opportunity and market size, is based on information from various sources, including those listed below, on assumptions based on such data and other similar sources, and on our knowledge of the markets for our solution. The market and industry information included in this prospectus involves a number of assumptions and limitations, and you are cautioned not to give undue weight to such information. In addition, projections, assumptions and estimates of our future performance and the future performance of the industry in which we operate are necessarily subject to a high degree of uncertainty and risk due to a variety of factors, including those described in “Risk Factors,” “Special Note Regarding Forward-Looking Statements” and elsewhere in this prospectus. These and other factors could cause results to differ materially from those expressed in the estimates made by the independent parties and by us.

Certain information in the text of the prospectus is contained in independent industry publications. The sources of these independent industry publications are provided below.

“The Rubicon Project” is our primary registered trademark. The prospectus contains this trademark and some of our other trademarks, trade names and service marks. Each trademark, trade name or service mark of any other company appearing in this prospectus belongs to its respective holder.

Certain monetary amounts, percentages and other figures included in this prospectus have been subject to rounding adjustments. Accordingly, figures shown as totals in certain tables may not be the arithmetic aggregation of the figures that precede them, and figures expressed as percentages in the text may not total 100% or, as applicable, when aggregated may not be the arithmetic aggregation of the percentages that precede them. In this prospectus, “Rubicon Project,” “we,” “us” and the “company” refer to The Rubicon Project, Inc. and, where appropriate, its subsidiaries, unless expressly indicated or the context otherwise requires. In this prospectus, references to our common stock prior to the offering refer to our Class A common stock and our Class B common stock together, unless expressly indicated or the context otherwise requires, and references to our common stock after the offering refer to the single class of common stock that we will have outstanding upon consummation of this offering.

We estimate that the net proceeds we receive from this offering will be approximately $72.2 million based on the initial public offering price of $15.00 per share after deducting the underwriting discount and commissions and estimated offering expenses payable by us. If the underwriters’ option to purchase additional shares in this offering from us is exercised in full, our estimated net proceeds will be approximately $86.4 million after deducting the underwriting discounts and commissions and estimated offering expenses payable by us. We will not receive any of the net proceeds from the sale of shares of our common stock in this offering by the selling stockholders.

The principal purposes of this offering are to create a public market for our common stock, obtain additional working capital, and facilitate our future access to the public equity markets, as well as to increase market awareness of our company and our standing among buyers and sellers and improve our competitive position. Our management will have broad discretion in the application of the net proceeds to us from this offering, and investors will be relying on the judgment of our management regarding the application of the proceeds. Pending their use, we plan to invest our net proceeds from this offering in short-term, interest-bearing obligations, investment-grade instruments, certificates of deposit or direct or guaranteed obligations of the U.S. government.

We intend to use the net proceeds from this offering for general corporate purposes, including working capital, sales and marketing activities, engineering initiatives including enhancement of our solution and investment in technology and development, general and administrative expenses and capital expenditures. We expect to use a portion of the net proceeds from this offering to hire additional personnel in connection with the activities described in the previous sentence. We also may use a portion of the net proceeds from this offering to acquire or invest in technologies, solutions or businesses that complement our business, although we have no present commitments to complete any such transactions.

We have never declared or paid any dividends on our common stock, and we do not anticipate paying any cash dividends in the future. We currently intend to retain any earnings to finance the operation and expansion of our business. Any future determination to pay dividends will be at the discretion of our board of directors and will be dependent upon then-existing conditions, including our earnings, capital requirements, results of operations, financial condition, business prospects and other factors that our board of directors considers relevant. See “Management’s Discussion and Analysis of Financial Condition and Results of Operations” for additional information regarding our financial condition. In addition, our credit facility contains restrictions on our ability to pay dividends.

You should read the following table in conjunction with the sections entitled “Use of Proceeds,” “Selected Consolidated Financial and Other Data,” “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and our consolidated financial statements and related notes included in this prospectus.

The number of shares of our common stock to be outstanding after this offering on a pro forma as adjusted basis giving effect to our sale of 5,416,796 shares of common stock in this offering is based on 26,551,195 shares of our common stock outstanding on a pro forma basis as noted above as of December 31, 2013, and excludes:

If you invest in our common stock, your interest will be diluted to the extent of the difference between the amount per share paid by purchasers of shares of common stock in this offering and the pro forma as adjusted net tangible book value per share of common stock immediately after the completion of this offering.

As of December 31, 2013, our pro forma net tangible book value was approximately $19.6 million, or $0.74 per share of common stock. Our pro forma net tangible book value per share represents the amount of our total tangible assets reduced by the amount of our total liabilities and divided by the total number of shares of our common stock outstanding as of December 31, 2013, giving effect to the conversion of all outstanding shares of our convertible preferred stock into shares of common stock, the net exercise of an outstanding warrant for 845,867 shares of our convertible preferred stock resulting in the issuance of 286,055 shares of common stock based on the initial public offering price of $15.00 per share and the reclassification of the preferred stock warrant liability to additional paid-in capital, each immediately prior to the completion of this offering.

After giving effect to our sale in this offering of shares of our common stock at the initial public offering price of $15.00 per share and after deducting underwriting discounts and commissions and estimated offering expenses payable by us, our pro forma as adjusted net tangible book value as of December 31, 2013 would have been approximately $91.8 million, or $2.87 per share of our common stock. This represents an immediate increase in pro forma as adjusted net tangible book value of $2.13 per share to our existing stockholders and an immediate dilution of $12.13 per share to investors purchasing shares in this offering.

The following table illustrates this per share dilution in net tangible book value to new investors after giving effect to this offering:

The following table summarizes, on a pro forma as adjusted basis as of December 31, 2013 after giving effect to (i) the automatic conversion of each outstanding share of our convertible preferred stock into one-half of a share of Class A common stock, (ii) the automatic conversion of each outstanding share of Class B common stock into one share of Class A common stock, (iii) the effectiveness of our amended and restated certificate of incorporation, providing for the conversion of our Class A common stock (including all shares of Class A common stock issued upon conversion of our convertible preferred stock and Class B common stock as described above) into a single class of common stock, (iv) the automatic conversion of an outstanding warrant exercisable for 25,174 shares of our convertible preferred stock into a warrant exercisable for 12,587 shares of common stock, (v) the net exercise of an outstanding warrant for 845,867 shares of our convertible preferred stock resulting in the issuance of 286,055 shares of common stock based on the initial public offering price of $15.00 per share, and (vi) the completion of this offering at the initial public offering price of $15.00 per share, the difference between existing stockholders and new investors with respect to the number of shares of common stock purchased from us, the total consideration paid to us and the average price per share paid, before deducting underwriting discounts and commissions and estimated offering expenses:

To the extent that the outstanding warrant or any of our outstanding options are exercised, investors will experience further dilution.

Except as otherwise indicated, the above discussion and tables assumes no exercise by the underwriters of their option to purchase up to an additional 1,015,649 shares from us. If the underwriters exercise their over-allotment option in full, our existing stockholders would own 80.5% and our new investors would own 19.5% of the total number of shares of our common stock outstanding upon the completion of this offering.

The number of shares of our common stock to be outstanding after this offering is based on 26,551,195 shares of our common stock outstanding as of December 31, 2013, and excludes:

The following table sets forth our selected consolidated historical financial and operating data for the periods indicated. The consolidated statements of operations data for the years ended December 31, 2011, 2012 and 2013 and the consolidated balance sheet data as of December 31, 2012 and 2013 have been derived from our audited consolidated financial statements included elsewhere in this prospectus.

The historical results presented below are not necessarily indicative of the results to be expected for any future period and our interim results are not necessarily indicative of the results to be expected for the full year or any other period. This information should be read in conjunction with “Risk Factors,” “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” and the consolidated financial statements and related notes included elsewhere in this prospectus.

Managed revenue is an operational measure that represents the advertising spending transacted on our platform, and would represent our revenue if we were to record our revenue on a gross basis instead of a net basis. Managed revenue does not represent revenue reported on a GAAP basis. We review managed revenue for internal management purposes to assess market share and scale. Many companies in our industry record revenue on a gross basis, so tracking our managed revenue allows us to compare our results to the results of those companies. Our managed revenue is influenced by the volume and characteristics of paid impressions, and average CPM.

Adjusted EBITDA is a non-GAAP financial measure defined by us as net loss adjusted for stock-based compensation expense, depreciation and amortization, interest (income) expense, net, change in fair value of convertible preferred stock warrant liabilities, and other income or expense, net, which mainly consists of foreign exchange gains and losses, net, certain other non-recurring income or expenses such as acquisition and related costs, and provision for income taxes. Adjusted EBITDA should not be considered as an alternative to net income, operating income or any other measure of financial performance calculated and presented in accordance with GAAP. Adjusted EBITDA eliminates the impact of items that we do not consider indicative of our core operating performance. You are encouraged to evaluate these adjustments and the reason we consider them appropriate. We believe Adjusted EBITDA is useful to investors in evaluating our operating performance for the following reasons:

The following table presents a reconciliation of net loss, the most comparable GAAP measure, to Adjusted EBITDA for each of the periods indicated:

You should read the following discussion and analysis of our financial condition and results of operations in conjunction with the consolidated financial statements and the related notes to the consolidated financial statements included later in this prospectus. In addition to historical financial information, the following discussion contains forward-looking statements that reflect our plans, estimates, beliefs and expectations that involve risks and uncertainties. Our actual results and the timing of events could differ materially from those discussed in these forward-looking statements. Factors that could cause or contribute to these differences include those discussed below and elsewhere in this prospectus, particularly in “Risk Factors” and “Special Note Regarding Forward-Looking Statements.”

We have direct relationships built on technical integration with over 700 sellers of digital advertising, including approximately 40% of the U.S. comScore 100. We believe that our direct relationships and integration with sellers, which differentiate us from many other participants in the advertising ecosystem, make us a vital participant in the digital advertising industry. Our integration of sellers into our platform gives sellers the ability to monetize a full variety and volume of inventory. At the same time, buyers leverage our platform to manage their advertising spending, simplify order management and campaign tracking, obtain actionable insights into audiences for their advertising and access impression level purchasing from hundreds of sellers. We believe buyers need our platform because of our powerful solution and our direct relationships and integration with some of the world’s largest websites and applications. Our solution is constantly self-optimizing based on our ability to analyze and learn from vast volumes of data. The additional data we obtain from the volume of transactions on our platform help make our machine-learning algorithms more intelligent, leading to higher quality matching

between buyers and sellers, better return on investment for buyers and higher revenue for sellers. As a result of that high quality matching, we attract even more sellers which in turn attracts more buyers and vice versa. We believe this self-reinforcing dynamic creates a strong platform for growth. The historical and real time data we derive from the over 700 seller integrations, 25 billion transactions per week, 3 trillion bid requests per month and 600 million Internet users globally that interact with our platform per month inform our machine-learning algorithms and thereby create a size, scale and capability that is difficult to replicate.

Since our incorporation in April 2007, we have invested in our solution to meet the complex needs of buyers and sellers of digital advertising. We have achieved significant growth as we have scaled our solution, including the functionality of our Advertising Automation Cloud and its applications for buyers and sellers. During our early stages, our solution helped sellers to automate their existing advertising network relationships to match the right buyer with each impression as well as increase their revenue and decrease their costs. Between 2008 and 2009, we developed direct relationships with buyers and created applications to assist buyers to increase their return on investment. During 2010, we added real time bidding, or “RTB,” capabilities, allowing sellers’ inventory to be sold in an auction to buyers, specifically, DSPs, creating a real time unified auction where buyers compete to purchase sellers’ advertising inventory. During 2012, we launched our private marketplace, which allows sellers to connect directly with pre-approved buyers to execute direct sales of previously unsold advertising inventory.

The automation of buying and selling of advertising, and in particular, RTB, has grown significantly and is projected to continue to grow. According to IDC, RTB spending was $2.7 billion in 2012, $4.5 billion in 2013 and is expected to reach $20.8 billion by 2017. We believe this trend will directly benefit us and our prospects for continued growth.

Large agencies, DSPs and ad networks, many of which are already established in size and scale, compose the majority of automated digital advertising spend. Accordingly, we believe our growth will be less affected by an increase in buyers than by increases in the amount of spend per buyer as more advertising shifts from traditional to automated buying and selling. We currently have over 700 sellers on our platform and believe that growth in the number of sellers may contribute to a larger marketplace and increased advertising spending.

Another industry trend is the expansion of automated buying and selling of advertising through new channels, such as mobile, and the expansion to new advertising units, such as video. We have only recently expanded our solution to include the mobile platform and have not yet expanded our advertising units to include video. If we are unable to effectively expand our offerings in these areas, our competitive position may weaken and our growth may be adversely affected. The growth of automated buying and selling advertising is also expanding into new markets, and in some markets the adoption of automated digital advertising is greater than in the United States. We intend to expand our business in existing territories served as well as new territories. If we are unable to localize our offerings and provide our solution in new territories, our growth may be impeded and our competitive position may weaken.

In addition to our continuous investment in our solution, we have incorporated functionalities into our solution through acquisitions. In 2009, we acquired Others Online, Inc., a digital advertising analytics company. In 2010 we acquired SiteScout Corporation, a malware and advertisement protection software company for digital display advertising. Also in 2010, we acquired Fox Audience Network, Inc., an advertising technology platform company, from News Corporation. In May 2012, we acquired MobSmith, Inc., a technology company focused on delivery of advertisements to mobile devices.

We generate revenue from buyers and sellers who use our solution for the purchase and sale of advertising inventory. Buyers use our solution to reach their intended audiences by purchasing advertising inventory that we make available from sellers through our solution. We recognize revenue upon the completion of a transaction, which is when an impression has been delivered to the consumer viewing a website or application, subject to satisfying all other revenue recognition criteria. We are responsible for the completion of the transaction. We bill

and collect the full purchase price of impressions from buyers. We report revenue net of amounts we pay sellers for the impressions they provide. In some cases, we generate revenue directly from sellers who maintain the primary relationship with buyers and utilize our solution to transact and optimize their activities.

For the years ended December 31, 2011, 2012 and 2013 our revenue was $37.1 million, $57.1 million, and $83.8 million, respectively, representing a year over year increase of 54% and 47% during 2012 and 2013, respectively. For the years ended December 31, 2011, 2012 and 2013, our net loss was $15.4 million, $2.4 million and $9.2 million, respectively. For the years ended December 31, 2011, 2012 and 2013 our Adjusted EBITDA was $(6.7) million, $9.2 million and $11.2 million, respectively. Adjusted EBITDA is a non-GAAP financial measure. For information on how we compute Adjusted EBITDA, and a reconciliation of Adjusted EBITDA to net loss on a GAAP basis, please refer to “Selected Consolidated Financial and Other Data.”

Substantially all of our revenue is U.S. revenue, determined based on the location of our legal entity that is a party to the relevant transaction.

We regularly review our key operational and financial performance measures, including those set forth below, to help us evaluate our business, measure our performance, identify trends affecting our business, establish budgets, measure the effectiveness of investments in our technology and development and sales and marketing, and assess our operational efficiencies. In addition to revenue, we also review managed revenue, and Adjusted EBITDA, which are discussed immediately following the table below. Revenue is discussed under the headings “—Components of Our Results of Operations” and “—Results of Operations.” We report our financial results as one operating segment. Our consolidated operating results, together with the following operating and financial measures, are regularly reviewed by our chief operating decision maker, principally to make decisions about how we allocate our resources and to measure our consolidated operating performance.

Our managed revenue has increased period over period as a result of increased adoption of our solution by buyers and sellers and increases in average CPM. We expect managed revenue to continue to grow with

increases in the volume of transactions on our platform or pricing, which can result from increases in the number of buyers or in advertising spending, and improvements in our auction algorithms. This increase may fluctuate due to seasonality and increases or decreases in average CPM and paid impressions. In addition, we generally experience higher managed revenue during the fourth quarter of a given year, resulting from higher advertising spending and more bidding activity, which may drive higher volumes of paid impressions or average CPMs.

Adjusted EBITDA is a non-GAAP financial measure defined by us as net loss adjusted for stock-based compensation expense, depreciation and amortization, interest (income) expense, net, change in fair value of convertible preferred stock warrant liabilities, and other income or expense, net, which mainly consists of foreign exchange gains and losses, net, certain other non-recurring income or expenses such as acquisition and related costs, and provision for income taxes. Our Adjusted EBITDA will be impacted by the rate at which our revenues increase and the timing of our investments in our operations. Please see “Selected Consolidated Financial and Other Data—Financial Measure” for information regarding the limitations of using Adjusted EBITDA as a financial measure and for a reconciliation of Adjusted EBITDA to net loss, the most directly comparable financial measure calculated in accordance with GAAP.

We generate revenue from buyers and sellers who use our solution for the purchase and sale of advertising inventory. Buyers use our solution to reach their intended audiences by buying advertising inventory that we make available from sellers through our solution. Our solution enables buyers and sellers to purchase and sell advertising inventory, matches buyers and sellers and establishes rules and parameters for open and transparent auctions of advertising inventory. We recognize revenue upon the completion of a transaction, that is, when an impression has been delivered to the consumer viewing a website or application, subject to satisfying all other revenue recognition criteria. We are responsible for the completion of the transaction. We generally bill and collect the full purchase price of impressions from buyers. We report revenue net of amounts we pay sellers for the impressions they provide. In some cases, we generate revenue directly from sellers who maintain the primary relationship with buyers and utilize our solution to transact and optimize their activities. Our accounts receivable are recorded at the amount of gross billings to buyers, net of allowances, for the amounts we are responsible to collect, and our accounts payable are recorded at the net amount payable to sellers. Accordingly, both accounts receivable and accounts payable appear large in relation to revenue reported on a net basis.

Our revenue, cash flow from operations, operating results and key operational and financial performance may vary from quarter to quarter due to the seasonal nature of advertiser spending or from other events that cause a spike in advertising activity. For example, many advertisers devote a disproportionate amount of their advertising budgets to the fourth quarter of the calendar year to coincide with increased holiday purchasing. Moreover, advertising inventory in the fourth quarter may be more expensive due to increased demand. Historically, the fourth quarter of the year reflects our highest level of revenue, and the first quarter reflects the lowest level of our revenue.

We expect revenue to continue to grow. However, revenue may be impacted by seasonality, the amounts we pay sellers and other factors such as changes in the market, our execution of the business, and competition.

Our revenue recognition policies are discussed in more detail under “—Critical Accounting Policies and Estimates.”

Cost of Revenue. Our cost of revenue consists primarily of data center costs, bandwidth costs, depreciation expense of hardware supporting our revenue producing platform, amortization of software costs for the development of our revenue producing platform, amortization expense associated with acquired developed technologies, personnel costs, and facilities related costs. Personnel costs include salaries, bonuses, stock-based compensation, and employee benefit costs, and are primarily attributable to personnel in our network operations group, who support our platform. We capitalize costs associated with software that is developed or obtained for internal use and amortize the costs associated with our revenue producing platform in cost of revenue over their estimated useful lives. Many of these expenses are fixed and do not increase or decrease proportionately with increases or decreases in our revenue. We expect cost of revenue to increase as we continue to invest additional capital into our data centers, hire additional personnel to continue to build and maintain our data centers, and invest in our internal use software. As a percentage of revenue, cost of revenue may fluctuate based on revenue levels and the timing of these investments.

Sales and Marketing. Our sales and marketing expenses consist primarily of personnel costs, including stock-based compensation and the sales bonuses paid to our sales organization, and marketing expenses such as brand marketing, travel expenses, trade shows and marketing materials, professional services, and to a lesser extent, facilities related costs, and depreciation and amortization. Our sales organization focuses on marketing

our solution to increase the adoption of our solution by existing and new buyers and sellers. We are also focused on expanding our international business, primarily by growing our sales team in certain countries in which we currently operate and establishing a presence in additional countries. As a result, we expect sales and marketing expenses to increase in absolute dollars in future periods. Sales and marketing expense as a percentage of revenue may fluctuate from period to period based on revenue levels and the timing of our investments in our sales and marketing functions as these investments may vary in scope and scale over periods and are impacted by the seasonality in our industry and business.

Technology and Development. Our technology and development expenses consist primarily of personnel costs, including stock-based compensation, and professional services, associated with the ongoing development and maintenance of our solution, and to a lesser extent, facilities related costs, and depreciation and amortization. These expenses include costs incurred in the development, implementation and maintenance of internal use software, including platform and related infrastructure. Technology and development costs are expensed as incurred, except to the extent that such costs are associated with internal use software development that qualifies for capitalization which are then recorded as internal use software development costs, net on our consolidated balance sheet. We amortize internal use software development costs that relate to our revenue producing activities or our platform to cost of revenue and amortize other internal use software development costs to technology and development costs or general and administrative expenses, depending on the nature of the related project. We believe that continued investment in our solution, including its technologies and functionalities, is critical to attaining our strategic objectives and long-term growth. We therefore expect technology and development expense to increase as we continue to invest in technology infrastructure to support an increased volume of advertising spending on our platform and international expansion, as well as to expand our engineering and technology teams to maintain and support our technology and development efforts. We also intend to invest in technology and development to enhance our solution, including in new and enhanced technologies and functionalities, and to further automate our business processes. Technology and development expense as a percentage of revenue may fluctuate from period to period based on revenue levels and the timing of these investments.

General and Administrative. Our general and administrative expenses consist primarily of personnel costs, including stock-based compensation, associated with our executive, finance, legal, human resources, compliance and other administrative personnel, as well as accounting and legal professional services fees, facilities related costs and depreciation, and other corporate related expenses. General and administrative expenses also include amortization of internal use software development costs that relate to general and administrative functions. We expect to continue to invest in corporate infrastructure and incur additional expenses associated with transition and operation as public company, including increased legal and accounting costs, investor relations costs, higher insurance premiums and compliance costs associated with developing the requisite infrastructure required to comply with Section 404 in the future. As a result, we expect general and administrative expenses to increase in absolute dollars in future periods.

Interest (Income) Expense, Net. Interest expense is mainly related to our credit facilities and capital lease arrangements. Interest income consists of interest earned on our money market accounts and was insignificant during the years ended December 31, 2011, 2012 and 2013.

Change in Fair Value of Convertible Preferred Stock Warrant Liability. We have two outstanding warrants to purchase shares of our preferred stock. The convertible preferred stock warrants are subject to re-measurement to fair value at each balance sheet date, and any change in fair value is recognized as a component of other expense, net. In connection with the closing of this offering, the warrants will either expire, be exercised for shares of common stock or convert into warrants to purchase shares of common stock and we will no longer be required to re-measure the converted common stock warrants to fair value.

Foreign Currency Exchange (Gain) Loss, Net. Foreign currency exchange (gain) loss, net consists primarily of gains and losses on foreign currency transactions. We have foreign currency exposure related to our accounts receivable and accounts payable that are denominated in currencies other than the U.S. Dollar, principally the British Pound and Euro.

Provision for income taxes consists primarily of federal, state and foreign income taxes. Due to uncertainty as to the realization of benefits from our domestic deferred tax assets, including net operating loss carryforwards and research and development tax credits, we have a full valuation allowance reserved against such assets. We expect to maintain this full valuation allowance in the near term.

The following tables set forth our consolidated results of operations and our consolidated results of operations as a percentage of revenue for the periods presented.

Revenue increased $26.8 million, or 47%, during the year ended December 31, 2013 compared to the year ended December 31, 2012. The increase in revenue was due to an increase in the amount of advertising spending on our platform during the year ended December 31, 2013 compared to the year ended December 31, 2012. This increase was primarily attributable to an increase of $0.12, or 50%, in average CPM during the year ended December 31, 2013 compared to the year ended December 31, 2012, representing an increase in revenue of approximately $30.5 million after consideration of our take rate. This increase in average CPM during the period was due to better targeting and other improved capabilities of our solution and, to a lesser extent, to an increase in the value of advertising inventory available from sellers. The increase in average CPM was partially offset by a decrease of 7% in paid impressions during the year ended December 31, 2013 compared to the year ended December 31, 2012, primarily attributable to our traffic quality control initiatives to maintain a high standard of quality advertising inventory and reduce lower quality traffic. These efforts resulted in a decrease in overall advertising inventory. The decrease in paid impressions reduced revenue by approximately $3.8 million after consideration of our take rate. The overall increase in revenue during the period reflects the continued adoption of our solution by buyers and sellers and the increasing efficiency and effectiveness of our solution.

Revenue increased $20.0 million, or 54%, during the year ended December 31, 2012 compared to the year ended December 31, 2011 primarily due to an increase of 451 billion, or 46%, in paid impressions transacted on our platform during the year ended December 31, 2012 compared to the year ended December 31, 2011. The increase in paid impressions was primarily attributable to increased bidding from buyers due to better matching, seller security features and other capabilities offered by our solution, in addition to the continued adoption of our solution by buyers and sellers and the increasing efficiency and effectiveness of our matching capabilities. Our take rate increased to 16.8% in 2012 from 15.5% in 2011, primarily due to the implementation and increased adoption of our real-time bidding and matching auctions.

Cost of revenue increased by $3.0 million, or 24%, during the year ended December 31, 2013 compared to the year ended December 31, 2012. This increase was primarily due to an increase in data center, hosting, and bandwidth costs of $1.4 million, an increase of $1.1 million in depreciation and amortization expense, including amortization of capitalized internal use software, and an increase in personnel costs of $0.4 million, each during the year ended December 31, 2013 compared to the year ended December 31, 2012. The increases in data center, hosting, and bandwidth costs were primarily attributable to data center locations added during the year ended December 31, 2013 in order to support the increase in bidding volume on our platform and resulting additional hardware, software, and maintenance expenses. The increase in depreciation and amortization was primarily attributable to increase in depreciation of computer equipment and network hardware and amortization of capitalized internal use software due to our continued investment in our revenue producing platform. The increase in personnel costs was primarily driven by increased headcount in order to support our growth. Average headcount attributable to cost of revenue increased by 34% during the year ended December 31, 2013 compared

to the year ended December 31, 2012. The amortization of capitalized internal use software reflected in cost of revenue was $1.9 million and $2.6 million for the years ended December 31, 2012 and 2013, respectively.

Cost of revenue decreased by $0.5 million, or 4%, during the year ended December 31, 2012 compared to the year ended December 31, 2011. This decrease resulted primarily from data center consolidation and lease renegotiation, resulting in a decrease in data center, hosting, and bandwidth costs of $1.1 million. This decrease was partially offset by a $0.9 million increase in depreciation and amortization, mainly attributable to an increase in amortization of capitalized internal use software due to our continued investment in our revenue producing platform.

Sales and marketing expense increased by $5.4 million, or 26%, during the year ended December 31, 2013 compared to the year ended December 31, 2012. This increase was primarily due to an increase in personnel expenses, including stock-based compensation, of $3.4 million and, to a lesser extent, an increase in marketing expenses of $0.9 million mainly related to our participation in industry events and tradeshows and related public relations activities. The increase in personnel expense was primarily due to an increase in sales and marketing headcount. Our sales and marketing headcount increased in order to support our sales efforts and continue to develop and maintain relationships with buyers and sellers, as well as to provide information to the market with respect to our solution. Average sales and marketing headcount increased by 20% during the year ended December 31, 2013 compared to the year ended December 31, 2012.

Sales and marketing expense increased by $2.7 million, or 15%, during the year ended December 31, 2012 compared to the year ended December 31, 2011. This increase was primarily due to an increase in personnel expenses, including stock-based compensation, of $1.4 million, due to an increase in headcount to support our sales and marketing efforts. Our sales and marketing headcount increased in order to support our sales efforts and continue to develop and maintain relationships with buyers and sellers, as well as to provide information to the market with respect to our solution. Average sales and marketing headcount increased by 36% during the year ended December 31, 2011 compared to the year ended December 31, 2012. In addition, marketing and promotional expenses increased by $0.4 million, mainly related to our participation in industry events and sponsorships and tradeshows.

Overall sales and marketing expenses increased due to our continued focus on marketing our platform and solution to increase the adoption of our platform and our solution by existing and new buyers and sellers, and to establish a presence in international markets.

Technology and development expense increased by $5.5 million, or 42%, during the year ended December 31, 2013 compared to the year ended December 31, 2012. This increase was primarily due to an increase in personnel expense of $4.7 million, including an increase in stock-based compensation of $0.8 million. The increase in personnel expense was primarily due to an increase in headcount, which reflects our continued hiring of engineers to maintain and support our technology and development efforts. Average technology and development headcount increased by 28% during the year ended December 31, 2013 compared to the year ended

December 31, 2012. Stock-based compensation increased due to grants to new hires and higher average per share values of stock-based awards driven by the increased fair value of our stock.

Technology and development expense increased by $0.6 million, or 5%, during the year ended December 31, 2012 compared to the year ended December 31, 2011. This increase was primarily due to an increase in depreciation and amortization of $0.3 million.

We capitalize a portion of our technology and development cost for the development of internal use software. The capitalized amounts related to our revenue producing platform are amortized to cost of revenue, amounts related to general and administrative functions are amortized to general and administrative expense, and the remainder of the capitalized amounts are amortized to technology and development. The timing of our capitalizable development and enhancement projects may affect the amount of development costs expensed in any given period. We capitalized $3.2 million, $3.9 million and $4.1 million of costs, primarily labor costs, during the years ended December 31, 2011, 2012 and 2013, respectively.

General and administrative expense increased by $15.6 million, or 126%, during the year ended December 31, 2013 compared to the year ended December 31, 2012. This increase was primarily due to an increase in personnel expense of $8.4 million, including an increase in stock-based compensation of $2.4 million, and an increase in professional services of $5.2 million. The increase in personnel costs was driven primarily by increased headcount to support our growth. Average general and administrative headcount increased by 55% from December 31, 2012 to December 31, 2013. Stock-based compensation increased due to grants to new hires and higher average per share values of stock-based awards driven by the increased fair value of our stock. The increase in third-party professional services was related to accounting, audit, tax and legal services as we continued to invest in our infrastructure, processes and controls to support our growth and in preparation for this offering and becoming a public company.

General and administrative expense increased by $3.4 million, or 38%, during the year ended December 31, 2012 compared to the year ended December 31, 2011. This increase was primarily due to an increase in personnel expense, including stock-based compensation, of $1.2 million and an increase in third-party professional services of $0.7 million. The increase in personnel costs was driven primarily by increased headcount. Average general and administrative headcount increased by 39% from December 31, 2011 to December 31, 2012. The increase in third-party professional services was related to accounting and legal services as we continued to invest in our infrastructure.

The increase in other expense, net of $4.1 million, during the year ended December 31, 2013 compared to the year ended December 31, 2012 primarily related to the increase of $3.6 million in the fair value of our convertible preferred stock warrant liabilities due to the increase in the valuation of our preferred stock from December 31, 2012 to December 31, 2013, and an increase in losses of $0.6 million on foreign currency transactions mainly related to increased volume on foreign denominated transactions and fluctuations in the British Pound in relation to the U.S. Dollar from January 1, 2013 to December 31, 2013.

The increase in other expense, net of $0.8 million during the year ended December 31, 2012 compared to the year ended December 31, 2011, relates to an increase of $0.2 million in the fair value of our convertible preferred stock warrant liabilities, decrease of $0.5 million in other income, and increase of $0.1 million in interest (income) expense, net, partially offset by a decrease in losses of $45,000 on foreign currency transactions. The increase in the fair value of the convertible preferred stock warrant liabilities was due to the increase in the valuation of our preferred stock from December 31, 2011 to December 31, 2012. The decrease in losses on foreign currency transactions was mainly related to fluctuations in the British Pound and Euro in relation to the U.S. Dollar from January 1, 2011 to December 31, 2012. During the year ended December 31, 2011, we recorded other income related to software development we performed for a third party, which was unrelated to our core operations.

Our provision for income taxes during the years ended December 31, 2011, 2012 and 2013 of $0.1 million, $0.1 million and $0.2 million, respectively, was primarily related to taxes due in foreign jurisdictions.

At December 31, 2013, we had U.S. federal net operating loss carryforwards, or NOLs, of approximately $36.7 million, which will begin to expire in 2027. At December 31, 2013, we had state NOLs of approximately $43.3 million, which will also begin to expire in 2027. At December 31, 2013, we had federal research and development tax credit carryforwards, or credit carryforwards, of approximately $3.0 million, which will begin to expire in 2027. At December 31, 2013, we had state research and development tax credits of approximately $2.4 million, which carryforward indefinitely. Utilization of certain NOLs and credit carryforwards may be subject to an annual limitation due to ownership change limitations set forth in the Code and similar state provisions. Any future annual limitation may result in the expiration of NOLs and credit carryforwards before utilization. A prior ownership change and certain acquisitions resulted in us having NOLs subject to insignificant annual limitations.

The following tables set forth our quarterly unaudited consolidated statements of operations data in dollars and as a percentage of total revenue for each of the eight quarters in the period ended December 31, 2013. We have prepared the quarterly unaudited consolidated statements of operations data on a basis consistent with the audited consolidated financial statements included elsewhere in this prospectus. In the opinion of management, the financial information in these tables reflects all adjustments, consisting only of normal recurring adjustments, which management considers necessary for a fair statement of this data. This information should be read in conjunction with the audited consolidated financial statements and related notes included elsewhere in this prospectus. The results of historical periods are not necessarily indicative of the results for any future period.

The following table sets forth our consolidated results of operations for the specified periods as a percentage of our revenue for those periods.

For information on how we define operational metrics and financial measures see “—Key Operational and Financial Measures.” For more information as to the limitations of using non-GAAP measurements, see “Selected Consolidated Financial and Other Data—Operational and Financial Measures.”

The following table presents a reconciliation of Adjusted EBITDA to net loss, the most directly comparable financial measure calculated in accordance with GAAP:

Our overall operating results fluctuate from quarter to quarter as a result of a variety of factors, some of which are outside our control. We have experienced rapid growth since our incorporation in April 2007, which has resulted in a substantial increase in our revenue and a corresponding increase in our expenses to support our growth. This rapid growth has also led to variations in our overall operating results based on the timing of our investments and resulting headcount growth in sales and marketing, technology and development, and general and administrative expenses from quarter to quarter. Our historical results should not be considered a reliable indicator of our future results of operations.

Our quarterly revenue increased quarter-over-quarter for each period presented, except in the three months ended March 31, 2013 compared to the three months ended December 31, 2012. The increases in quarterly revenue are generally due to increases in the amount of advertising spending on our platform and increases in CPM. Our revenue also tends to be seasonal in nature, with the fourth quarter of each calendar year historically representing the largest percentage of our revenue for the year. Many advertisers spend the largest portion of their advertising budgets during the fourth quarter in preparation for the holiday shopping season, and as a result, we experience the impact of the increased spending from buyers in the fourth quarter, as reflected in our revenues for the three months ended December 31, 2012, and the impact of decreased spending from buyers in the first quarter, as reflected in our revenues in the three months ended March 31, 2013 as compared to the three months ended December 31, 2012.

Total expenses increased during every quarter presented in a given year, primarily due to increased expenses related to the continued expansion of, and investments in, our technical infrastructure, and expenses related to increases in employee headcount, including facilities related costs, depreciation and amortization, and stock-based compensation expense. Total expenses as a percentage of revenue may fluctuate quarter over quarter due to the timing of investments we make in our operations.

Our Adjusted EBITDA increased during the three months ended December 31, 2012 compared to three months ended March 31, 2012, June 30, 2012, and September 30, 2012 due to seasonal factors. Subsequently, due to seasonality, our Adjusted EBITDA decreased in the three months ended March 31, 2013 compared to the three months ended December 31, 2012. Our Adjusted EBITDA increased during the three months ended December 31, 2013 compared to the three months ended March 31, 2013, June 30, 2013, and September 30,

2013, also due to seasonal factors, consistent with the trends during 2012. Our Adjusted EBITDA decreased during the three months ended September 30, 2013 compared to the three months ended June 30, 2013 primarily due to increased professional fees related to accounting, audit, tax and legal third-party services as we continued to invest in our infrastructure, processes and controls to support our growth and in preparation for this offering and becoming a public company.

Since our incorporation in April 2007, we have primarily financed our operations and capital expenditures through private sales of convertible preferred stock, our use of our credit facilities, and cash generated from operations. Between 2007 and 2010, we raised $52.6 million from the sale of preferred stock.

At December 31, 2013, we had cash of $30.0 million and restricted cash of $1.7 million.

In March 2009, we entered into a credit facility with Silicon Valley Bank that provided for an asset based revolving credit facility and equipment term loan facilities. The credit facility was amended most recently in September 2013, among other changes to: increase the revolving loan commitment to $40.0 million, subject to continuing availability under the borrowing base thereunder, which is currently based on a percentage of certain accounts receivable; eliminate the equipment term loan facilities; and extend the stated maturity date to September 27, 2018. The aggregate revolving loan commitment under the credit facility may be increased to $70.0 million at the discretion of Silicon Valley Bank.

At December 31, 2013, we had $3.8 million in debt obligations under this credit facility and $36.2 million available for additional borrowings. We may prepay outstanding amounts under the credit facility without penalty and with nominal prepayment costs.

At our option, loans under the credit facility may bear interest based on either the LIBOR rate or the prime rate plus, in each case, an applicable margin. The applicable margins under the credit facility are (i) 2.00% or 3.50% per annum in the case of LIBOR rate loans, and (ii) 0.00% or 1.50% per annum in the case of prime rate loans (based on Silicon Valley Bank’s net exposure to us after giving effect to unrestricted cash held at Silicon Valley Bank and its affiliates plus up to $3.0 million held at other institutions). In addition, an unused revolver fee in the amount of 0.15% per annum of the average unused portion of the credit facility is payable by us to Silicon Valley Bank monthly in arrears.

Our credit facility restricts our ability to, among other things, sell assets, make changes to the nature of our business, engage in mergers or acquisitions, incur, assume or permit to exist additional indebtedness and guarantees, create or permit to exist liens, pay dividends, make distributions or redeem or repurchase capital stock or make other investments, engage in transactions with affiliates and make payments in respect of subordinated debt.

In addition, in the event that the amount available to be drawn is less than 20% of the maximum line amount of the credit facilities, or if an event of default exists, we are required to satisfy a minimum fixed charge coverage ratio test of 1.10 to 1.00. Currently, we would not satisfy this minimum fixed charge coverage ratio test, which is defined as a ratio of Adjusted EBITDA to the sum of interest accrual and principal payments required to be paid during the relevant measurement period. However, we meet the specified excess availability threshold, so we are not currently required to satisfy this test. At December 31, 2013 our fixed charge coverage ratio was (3.93) to 1.00.

The credit facility also includes customary representations and warranties and affirmative covenants. In addition, prior to amending our credit facility in September 2013, we were not compliant with an administrative covenant relating to the timing of delivery of audited financial statements, for which we have received waivers from Silicon Valley Bank in each instance. In addition to such other events of defaults as are customarily included in a credit facility, including a change of control default, our credit facility also includes an event of

default in the event a material adverse change occurs (as defined in the credit facility). Following an event of default, Silicon Valley Bank would be entitled to, among other things, accelerate payment of amounts due under the credit facility and exercise all rights of a secured creditor. We were in compliance with the covenants under the credit facility at December 31, 2013.

We believe our existing cash and cash flow from operations, together with the undrawn balance under our credit facility with Silicon Valley Bank, will be sufficient to meet our working capital requirements for at least the next 12 months. However, our liquidity assumptions may prove to be incorrect, and we could utilize our available financial resources sooner than we currently expect. Our future capital requirements and the adequacy of available funds will depend on many factors, including those set forth in the section of this prospectus entitled “Risk Factors.”

In the future, we may attempt to raise additional capital through the sale of equity securities or through equity-linked or debt financing arrangements. If we raise additional funds by issuing equity or equity-linked securities, the ownership of our existing stockholders will be diluted. If we raise additional financing by the incurrence of indebtedness, we will be subject to increased fixed payment obligations and could also be subject to restrictive covenants, such as limitations on our ability to incur additional debt, and other operating restrictions that could adversely impact our ability to conduct our business. Any future indebtedness we incur may result in terms that could be unfavorable to equity investors.

There can be no assurances that we will be able to raise additional capital or obtain such waivers or amendments on acceptable terms or at all, which would adversely affect our ability to achieve our business objectives. In addition, if our operating performance during the next twelve months is below our expectations, our liquidity and ability to operate our business could be adversely affected.

Cash provided by operating activities is primarily influenced by increases in collections from buyers and the related payments to sellers, as well as our investment in personnel and infrastructure to support the anticipated growth of our business. Cash provided by operating activities has been further increased by changes in our working capital, particularly changes in accounts receivable and accounts payable. The timing of cash receipts from buyers and payments to sellers can significantly impact our cash provided by operations for any period presented. We typically collect from buyers in advance of payments to sellers by approximately 15 to 20 days. Our working capital cycle was relatively consistent for all periods presented. During the fourth quarter, our working capital needs may increase due to the seasonality in our business. In addition, we expect seasonality to impact cash flows provided by operating activities on a sequential quarter and quarter over quarter basis.

For the year ended December 31, 2011, cash provided by operating activities of $2.1 million resulted from our net loss of $15.4 million, offset by non-cash expenses of $7.8 million and net changes in our working capital of $9.8 million. The net change in working capital was primarily related to an increase in accounts payable and accrued expenses of approximately $18.4 million offset by an increase in accounts receivable of approximately $8.0 million, both due to the growth in our revenues, the timing of cash receipts from buyers and the timing of payments to sellers.

For the year ended December 31, 2012, cash provided by operating activities of $15.6 million resulted from our net loss of $2.4 million, offset by non-cash expenses of $10.2 million and net changes in our working capital of $7.8 million. The net change in working capital was primarily related to an increase in accounts payable and accrued expenses of approximately $32.3 million, and an increase in other liabilities of approximately $1.7 million, offset by an increase in accounts receivable of approximately $26.3 million, both due to the growth in our revenues, the timing of cash receipts from buyers, and the timing of payments to sellers.

For the year ended December 31, 2013, cash provided by operating activities of $21.1 million resulted from our net loss of $9.2 million offset by non-cash expenses of $19.0 million and net changes in our working capital of $11.4 million. The net change in working capital was primarily related to an increase in accounts payable and accrued expenses of approximately $39.2 million, offset by an increase in accounts receivable of approximately $27.1 million, due to the timing of cash receipts from buyers, the timing of payments to sellers, and the seasonality of our business.

Our primary investing activities have consisted of purchases of property and equipment in support of our expanding headcount as a result of our growth, capital expenditures to develop our internal use software in support of creating and enhancing our technology infrastructure, and for cash used in acquisitions. Purchases of property and equipment may vary from period-to-period due to the timing of the expansion of our operations, the addition of headcount and the development cycles of our internal use software development costs. As our business grows, we expect our capital expenditures and our investment activity to continue to increase.

During the year ended December 31, 2011, we used $8.1 million of cash in investing activities, consisting of $3.7 million of investments in property and equipment, net of amounts reflected in accounts payable and accrued expenses at December 31, 2011, and $3.2 million of investments in our internal use software. In addition, during the year ended December 31, 2011, we paid $1.3 million that we had previously accrued related to an acquisition that occurred in 2010.

During the year ended December 31, 2012, we used $9.0 million of cash in investing activities, consisting of $3.7 million of investments in our internal use software and $3.0 million of investments in property and equipment, net of amounts reflected in accounts payable and accrued expenses at December 31, 2012 and net of amounts financed through capital leases. In addition, during the year ended December 31, 2012, we used $1.7 million for the acquisition of MobSmith, Inc., net of cash acquired. In conjunction with software license agreements, we reclassified $0.6 million of cash to restricted cash.

During the year ended December 31, 2013, we used $11.9 million of cash in investment activities, consisting of $6.8 million of investments in property and equipment, $3.9 million of investments in our internal use software, and $1.2 million of cash reclassified to restricted cash in conjunction with our corporate office building lease. During the year ended December 31, 2013, we continued to invest in property and equipment and internal use software to support our growth and increased headcount, expand our data center capabilities, and increase the functionality of our solution. In addition, during the year ended December 31, 2013, we relocated our corporate headquarters, in connection with which we incurred additional leasehold improvement costs.

Our financing activities have consisted primarily of net proceeds from the borrowings under our Silicon Valley Bank credit facility, including the equipment loans, and the issuance of shares of common stock upon the exercise of stock options.

During the year ended December 31, 2011, cash provided by financing activities of $1.3 million was primarily due to borrowings of $2.0 million from our equipment loans with Silicon Valley Bank and proceeds of $0.2 million from stock option exercises, partially offset by payments of $0.9 million on our equipment loan and capital lease obligations.

During the year ended December 31, 2012, cash used in financing activities of $1.4 million was primarily due to payments of $1.5 million on our equipment loan and capital lease obligations, partially offset by proceeds of $0.1 million from stock option exercises.

During the year ended December 31, 2013, cash used in financing activities of $0.8 million was primarily due to payments of $1.0 million on our equipment loan and capital lease obligations and payments of offering costs to our professional advisors of $0.5 million related to our initial public offering, partially offset by proceeds of $0.9 million from stock option exercises.

We do not have any relationships with other entities or financial partnerships, such as entities often referred to as structured finance or special purpose entities that have been established for the purpose of facilitating off-balance sheet arrangements or other contractually narrow or limited purposes. We did not have any other off balance sheet arrangements at December 31, 2013 other than preferred stock cumulative dividends, the operating leases, and the indemnification agreements described below.

The holders of our convertible preferred stock are entitled to dividends when, as, and if declared by our board of directors, and prior and in preference to common stock. Unless declared, dividends are not payable except that cumulative dividends are payable in the event of the sale, liquidation, dissolution, or winding up of the company. No dividends have been declared or paid to date. Immediately upon the closing of this offering, each outstanding share of convertible preferred stock will be automatically converted into one-half of a share of our common stock and these holders will no longer be entitled to cumulative dividends. Cumulative undeclared preferred stock dividends as of December 31, 2013 were $19.7 million.

Our principal commitments consist of obligations under our outstanding credit facility with Silicon Valley Bank, leases for our various office facilities, including our corporate headquarters in Los Angeles, California, and non-cancelable operating lease agreements with data centers that expire through 2018. In certain cases, the terms of the lease agreements provide for rental payments on a graduated basis.

The following table summarizes our contractual obligations at December 31, 2013:

Subsequent to December 31, 2013, we entered into new operating leases for office facilities in New York, Seattle and Berlin. Future non-cancelable minimum commitments relating to these operating leases totaling $3.9 million are due from February 2014 through April 2019.

At December 31, 2013, liabilities for unrecognized tax benefits of $1.5 million, which are attributable to U.S. income taxes, are not included in the table above because, due to their nature, there is a high degree of uncertainty regarding the time of future cash outflows and other events that extinguish these liabilities. In the ordinary course of business, we enter into agreements with sellers, buyers and other third parties pursuant to which we agree to indemnify buyers, sellers, vendors, lessors, business partners, lenders, stockholders, and other parties with respect to certain matters, including, but not limited to, losses resulting from claims of intellectual property infringement, damages to property or persons, business losses, or other liabilities. Generally these

indemnity and defense obligations relate to our own business operations, obligations, and acts or omissions. However, under some circumstances, we agree to indemnify and defend contract counterparties against losses resulting from their own business operations, obligations, and acts or omissions, or the business operations, obligations, and acts or omissions of third parties. These indemnity provisions generally survive termination or expiration of the agreements in which they appear. In addition, we have entered into indemnification agreements with our directors, executive officers and certain other officers that will require us, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors, officers or employees. No demands have been made upon us to provide indemnification under such agreements and there are no claims that we are aware of that could have a material effect on our consolidated financial statements.

Our consolidated financial statements are prepared in accordance with GAAP. The preparation of these consolidated financial statements requires us to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenue, expenses and related disclosures. We evaluate our estimates and assumptions on an ongoing basis. Our estimates are based on historical experience and various other assumptions that we believe to be reasonable under the circumstances. Our actual results could differ from these estimates.

We believe that the assumptions and estimates associated with the evaluation of revenue recognition criteria, including the determination of revenue recognition as net versus gross in our revenue arrangements, internal-use software development costs, the valuation of common stock, including assumptions used in the Black-Scholes option pricing model to determine the fair value of stock options and stock-based compensation expense, the valuation of preferred stock warrant liabilities, the assumptions used in the valuation of acquired assets and liabilities in business combinations, and income taxes, including the realization of tax assets and estimates of tax liabilities, have the greatest potential impact on our consolidated financial statements. Therefore, we consider these to be our critical accounting policies and estimates. For further information on all of our significant accounting policies, see the notes to our consolidated financial statements.

We have identified several material weaknesses in our internal control over financial reporting. For additional information, see the risk factor entitled “We have identified certain material weaknesses in our internal control over financial reporting. Failure to maintain effective internal controls could cause our investors to lose confidence and adversely affect the market price of our common stock. If our internal controls are not effective, we may not be able to accurately report our financial results or prevent fraud.”

We generate revenue from buyers and sellers who use our solution for the buying and selling of advertising inventory. We recognize revenue when four basic criteria are met: (i) persuasive evidence of an arrangement exists, (ii) delivery has occurred or services have been rendered, (iii) the fees are fixed or determinable, and (iv) collectibility is reasonably assured. We maintain separate arrangements with each buyer and seller in the form of master agreements, which set out the terms of the relationship and access to our solution, or insertion orders which specify price and volume requests. We also generate revenue directly from sellers who maintain the primary relationship with buyers and utilize our solution. In applying the foregoing criteria, we recognize revenue upon the completion of a transaction, that is, when an impression has been delivered to the consumer viewing a website or application. We assess whether fees are fixed or determinable based on impressions delivered and the contractual terms of the arrangements. Subsequent to the delivery of an impression, the fees are generally not subject to adjustment or refund. Historically, any refunds and adjustments have not been material. We assess collectability based on a number of factors, including the creditworthiness of a buyer and seller and payment history. Our revenue arrangements do not include multiple deliverables. We generally bill buyers for the gross amount of advertising inventory they purchase plus fees, if any, and we remit to a seller the amount spent by the buyer for the advertising inventory purchased less our fees.

We also report revenue in conformity with Revenue Recognition-Principal Agent Considerations. The determination of whether we are the principal or agent, and hence whether to report revenue on a gross basis for the amount of the advertising inventory buyers purchase using our platform, plus fees, if any, or on a net basis for the amount of fees charged to the buyer, if any, and fees retained from or charged to the seller, requires us to evaluate a number of indicators, none of which is presumptive or determinative. Our solution enables buyers and sellers to purchase and sell advertising inventory, matches buyers and sellers and establishes rules and parameters for advertising inventory transactions. Pricing is generally determined through our auction process. We do not purchase advertising inventory. As a result of these and other factors, we have determined we are not the principal in the purchase and sale of advertising inventory in all of our arrangements and we therefore report revenue on a net basis.

We capitalize certain internal use software development costs associated with creating and enhancing internally developed software related to our technology infrastructure. These costs include personnel and related employee benefit expenses for employees who are directly associated with and who devote time to software projects, and external direct costs of materials and services consumed in developing or obtaining software. Software development costs that do not meet the qualification for capitalization, as further discussed below, are expensed as incurred and recorded in technology and development expenses in the results of operations.

Software development activities generally consist of three stages, (i) the planning phase, (ii) the application and infrastructure development stage, and (iii) the post implementation stage. Costs incurred in the planning and post implementation phases of development of our software technologies, including costs associated with the post-configuration training and repairs and maintenance of the developed technologies, are expensed as incurred. We capitalize costs associated with software developed for internal use when both the preliminary project stage is completed and management has authorized further funding for the completion of the project. Costs incurred in the application and infrastructure development stage, including significant enhancements and upgrades, are capitalized. Capitalization ends once a project is substantially complete and the software and technologies are ready for their intended purpose. Internal use software development costs are amortized using a straight-line method over the estimated useful life of three years, commencing when the software is ready for its intended use. We believe the straight-line recognition method approximates the manner in which the expected benefit will be derived.

We do not transfer ownership of our software to, or lease our software to, third parties.

Compensation expense related to employee stock-based awards is measured and recognized in the financial statements based on the fair value of the awards granted. The fair value of each option award is estimated on the grant date using the Black-Scholes option-pricing model. Stock-based compensation expense is recognized on a straight-line basis, net of forfeitures, over the requisite service periods of the awards, which is generally four years.

Stock-based awards issued to non-employees are accounted for at fair value determined by using the Black-Scholes option-pricing model. We believe that the fair value of the stock options is more reliably measured than the fair value of the services received. The fair value of each non-employee stock-based compensation award is re-measured each period until a commitment date is reached, which is generally the vesting date.

Determining the fair value of stock-based awards at the grant date requires judgment. Our use of the Black-Scholes option-pricing model requires the input of subjective assumptions, including the fair value of the underlying common stock, the expected term of the option, the expected volatility of the price of our common stock, risk-free interest rates, and the expected dividend yield of our common stock. The assumptions used in our

option-pricing model represent management’s best estimates. These estimates involve inherent uncertainties and the application of management’s judgment. If factors change and different assumptions are used, our stock-based compensation expense could be materially different in the future.

Fair Value of Common Stock. Because there is no public market for the company’s common stock, our board of directors has determined the fair value of the common stock at the time of the grant of options and restricted stock awards by considering a number of objective and subjective factors discussed under “Common Stock Valuation” below.

Risk-Free Interest Rate. We base the risk-free interest rate used in the Black-Scholes option-pricing model on the yields of U.S. Treasury securities with maturities appropriate for the term of employee stock option awards.

Expected Term. The expected term of employee stock options represents the weighted-average period that the stock options are expected to remain outstanding. Given insufficient historical data relating to stock-option exercises, to determine the expected term, we apply the simplified approach, in which the expected term of an award is presumed to be the mid-point between the vesting date and the expiration date of the award.

Volatility. Because we do not have a trading history for our common stock, we determine the expected volatility based on the historical volatilities of our publicly traded peer group based on daily price observations over a period equivalent to the expected term of the stock option grants. Industry peers consist of several public companies in the industry that represent similar, but alternative investment opportunities to an investment in our Company. We did not rely on implied volatilities of traded options in our industry peers’ common stock because the volume of activity was relatively low. We intend to continue to consistently apply this process using the same or similar public companies until a sufficient amount of historical information regarding the volatility of our own common stock share price becomes available, or unless circumstances change such that the identified companies are no longer similar to us, in which case, more suitable companies whose share prices are publicly available would be utilized in the calculation.

Dividend Yield. The dividend yield assumption is based on our history and current expectations of dividend payouts. We have never declared or paid any cash dividends on our common stock, and we do not anticipate paying any cash dividends in the foreseeable future and, consequently, we used an expected dividend yield of zero.

The following table summarizes the weighted-average assumptions used in the Black-Scholes option-pricing model to determine the fair value of our stock options as follows:

In addition to the assumptions used in the Black-Scholes option-pricing model, we must also estimate a forfeiture rate to calculate the stock-based compensation expense for our awards. Our forfeiture rate is based on an analysis of our historical forfeitures and expected future forfeiture trends. We will continue to evaluate the appropriateness of the forfeiture rate based on historical forfeiture experience, analysis of employee turnover, and other factors. Quarterly changes in the estimated forfeiture rate may have a significant impact on our stock-based compensation expense as the cumulative effect of adjusting the rate is recognized in the period the forfeiture

estimate is changed. If a revised forfeiture rate is higher than the previously estimated forfeiture rate, an adjustment is made that will result in a decrease to the stock-based compensation expense recognized in the consolidated financial statements. If a revised forfeiture rate is lower than the previously estimated forfeiture rate, an adjustment is made that will result in an increase to the stock-based compensation expense recognized in the consolidated financial statements.

We will continue to use judgment in evaluating the assumptions related to our stock-based compensation. Future expense amounts for any particular period could be affected by changes in our assumptions or market conditions.

Due to the full valuation allowance provided with regard to our net deferred tax assets, we have not recorded any tax benefit attributable to stock-based awards for the years ended December 31, 2011, 2012 and 2013.

We are required to estimate the fair value of the common stock underlying our stock-based awards when performing the fair value calculations with the Black-Scholes option-pricing model. The fair values of the common stock underlying our stock-based awards were determined by our board of directors, with input from management and contemporaneous third-party valuations. We believe that our board of directors has the relevant experience and expertise to determine the fair value of our common stock. As described below, the exercise price of our stock options was determined by our board of directors with reference to the most recent contemporaneous third-party valuation as of the grant date.

Given the absence of a public trading market of our common stock, and in accordance with the practice aid issued by the American Institute of Certified Public Accountants Practice Guide, Valuation of Privately-Held-Company Equity Securities Issued as Compensation, our board of directors exercised reasonable judgment and considered numerous objective and subjective factors to determine the best estimate of the fair value of our common stock, including:

In valuing our common stock, our board of directors determined the equity value of our business using the market comparable approach valuation method and, beginning in March 1, 2013 the income approach valuation method. The market comparable approach estimates value based on a comparison of the subject company to comparable public companies in a similar line of business. From the comparable companies, a representative market value multiple is determined and then applied to the subject company’s operating results to estimate the value of the subject company. To determine our peer group of companies, we considered public software and digital advertising companies and selected those that that represent similar, but alternative investment opportunities to an investment in our Company. From time to time, we updated the set of comparable companies as new or more relevant information became available.

The income approach estimates value based on the expectation of future cash flows that a company will generate. These future cash flows are discounted to their present values using a discount rate derived from an analysis of the cost of capital of comparable publicly traded companies in our industry or similar lines of business as of each valuation date and is adjusted to reflect the risks inherent in our cash flows. Once we determined an equity value, we used the option pricing method, or OPM, to allocate the equity value to each of our classes of stock. The OPM values each equity class by creating a series of call options on our equity value, with exercise prices based on the liquidation preferences, participation rights, and strike prices of the equity instruments. This method is generally preferred when a discrete set of future outcomes is not transparent or are difficult to predict, and dissolution or liquidation is not imminent. Starting in March 2013, due to greater clarity on potential liquidity scenarios, we began using the Probability Weighted Expected Return Method, or PWERM, to allocate our equity value among the various outcomes. Using the PWERM, the value of our common stock is estimated based upon a probability-weighted analysis of varying values for our common stock assuming possible future events for our Company, such as:

Application of these approaches involves the use of estimates, judgment and assumptions, such as revenue, expenses and future cash flows and selection of comparable companies. Changes in our assumptions or the interrelationship of those assumptions impacted the valuations as of each valuation date.

In addition, we also considered an appropriate discount adjustment to recognize the lack of marketability and liquidity due to the fact that stockholders of private companies do not have access to trading markets similar to those enjoyed by stockholders of public companies. The discount for marketability was determined using a protective put option model, in which a put option is used as a proxy for measuring discounts for lack of marketability of securities.

From time to time, we updated the set of comparable companies as new or more relevant information became available. Compared to the September 30, 2012 valuation, for the March 1, 2013 valuation, we eliminated four comparable companies and added new comparable companies based on our growth rates and current size. The set of comparable companies was the same for the March 1, 2013 and June 1, 2013 valuations. For the October 1, 2013 valuation, we added four new comparable companies. Each newly added company was in the digital advertising/services industry and had recently completed its initial public offering, providing publicly available financial data from which valuation multiples could be derived. The set of comparable companies was consistent with the set used in the calculation of the non-marketability discount. The market multiples are based on key metrics of comparable publicly traded companies, including high-growth companies in the digital advertising sector.

Between December 13, 2012 and the date of this prospectus, we granted the following stock options:

On March 3, 2014, our board of directors approved the issuance of 2,200,371 shares of restricted stock to our employees and consultants.

Based on the initial public offering price of $15.00 per share, the aggregate intrinsic value of options outstanding as of December 31, 2013 was approximately $74.1 million, of which $34.2 million related to vested options and approximately $39.9 million related to unvested options.

At December 31, 2013, we had unrecognized stock-based compensation related to stock options of approximately $17.3 million which is expected to be recognized over a weighted-average period of 2.6 years.

As a result of the March 3, 2014 option grants and restricted stock issuance, we expect to recognize additional stock-based compensation expense of approximately $40.0 million primarily over the next four years.


	Initial public offering price		Underwriting discount (1)		Proceeds to us (before expenses)		Proceeds to the selling stockholders (before expenses)
Per Share	$	15.00	$	1.05	$	13.95	$	13.95
Total	$	101,564,925	$	7,109,545	$	75,564,304	$	18,891,076


MORGAN STANLEY	GOLDMAN, SACHS & CO.	RBC CAPITAL MARKETS

Needham & Company	Oppenheimer & Co.	LUMA Securities


	Page
Prospectus Summary		1
Risk Factors		16
Special Note Regarding Forward-Looking Statements		51
Market and Industry Data and Other Information		52
Use of Proceeds		53
Dividend Policy		54
Capitalization		55
Dilution		58
Selected Consolidated Financial And Other Data		60
Management’s Discussion And Analysis Of Financial Condition And Results Of Operations		64
Business		93
Management		114
Executive Compensation		121
Principal And Selling Stockholders		132
Certain Relationships And Related Transactions		137
Description Of Capital Stock		139
Shares Eligible For Future Sale		143
Material U.S. Federal Income Tax Consequences To Non-U.S. Holders Of Our Common Stock		145
Underwriting		149
Legal Matters		155
Experts		155
Where You Can Find More Information		155
Index To Consolidated Financial Statements		F-1


	As of December 31, 2013
	Actual			Pro Forma			Pro Forma As Adjusted
	(in thousands, except share data)
Cash and cash equivalents	$	29,956		$	29,956		$	102,642

Debt and capital lease arrangements, including current portion:
Capital leases		393			393			393
Credit facility		3,788			3,788			3,788

Total debt and capital leases, including current portion		4,181			4,181			4,181
Convertible preferred stock, $0.00001 par value per share (29,691,524 shares authorized and 28,820,481 shares issued and outstanding, actual; no shares issued and outstanding, pro forma and pro forma as adjusted)		52,571			—			—
Stockholders Equity (Deficit):
Preferred stock, $0.00001 par value per share (no shares authorized or issued and outstanding, actual; 10,000,000 shares authorized, and no shares issued and outstanding, pro forma and pro forma as adjusted)		—			—			—
Class A common stock, $0.00001 par value per share (32,500,000 shares authorized and 7,664,844 shares issued and outstanding, actual; no shares authorized, issued and outstanding, pro forma and pro forma as adjusted)		—			—			—
Class B common stock, $0.00001 par value per share (4,190,063 shares authorized and 4,190,063 shares issued and outstanding, actual; no shares authorized, issued and outstanding, pro forma and pro forma as adjusted)		—			—			—
Common stock, $0.00001 par value per share (no shares authorized or issued and outstanding, actual; 500,000,000 shares authorized and 26,551,195 shares issued and outstanding, pro forma; and 500,000,000 shares authorized and 31,967,991 shares issued and outstanding, pro forma as adjusted)		—			—			—
Additional paid-in capital		25,532			83,554			155,744
Accumulated other comprehensive income		96			96			96
Accumulated deficit		(62,039	)		(62,039	)		(62,039	)

Total stockholders’ equity (deficit)		(36,411	)		21,611			93,801

Total capitalization	$	20,341		$	25,792		$	97,982


	Shares Purchased					Total Consideration					Average Price Per Share
	Number		Percent			Amount		Percent			Average Price Per Share
	(in thousands, except percentages and per share data)
Existing stockholders		26,551		83.1	%	$	66,775		45.1	%	$	2.51
New public investors		5,417		16.9			81,252		54.9			15.00

Total		31,968		100.0	%	$	148,027		100.0	%	$	4.63


Initial public offering price per share			$	15.00
Pro forma net tangible book value per share as of December 31, 2013	$	0.74
Increase in pro forma net tangible book value per share attributable to new investors		2.13

Pro forma as adjusted net tangible book value per share after this offering		2.87

Dilution per share to new investors in this offering			$	12.13


	Three Months Ended
	Mar. 31, 2012			June 30, 2012			Sept. 30, 2012			Dec. 31, 2012		Mar. 31, 2013			June 30, 2013			Sept. 30, 2013			Dec. 31, 2013
	(in thousands)
Revenue	$	10,763		$	13,010		$	13,853		$	19,446	$	16,600		$	19,035		$	20,063		$	28,132
Expenses:
Cost of revenue⁽¹⁾		2,817			2,842			3,093			3,615		3,437			3,594			4,181			4,146
Sales and marketing⁽¹⁾		4,627			5,261			4,939			5,631		6,195			6,167			6,405			7,044
Technology and development⁽¹⁾		2,586			2,979			3,783			3,767		4,111			5,138			4,823			4,543
General and administrative⁽¹⁾		2,405			2,718			3,355			3,853		4,634			5,726			7,603			9,963

Total expenses		12,435			13,800			15,170			16,866		18,377			20,625			23,012			25,696

Income (loss) from operations		(1,672	)		(790	)		(1,317	)		2,580		(1,777	)		(1,590	)		(2,949	)		2,436
Other (income) expense, net		60			277			164			528		335			452			1,922			2,413

Income (loss) before income taxes		(1,732	)		(1,067	)		(1,481	)		2,052		(2,112	)		(2,042	)		(4,871	)		23
Provision for income taxes		30			32			41			31		50			63			74			60

Net income (loss)	$	(1,762	)	$	(1,099	)	$	(1,522	)	$	2,021	$	(2,162	)	$	(2,105	)	$	(4,945	)	$	(37	)


	Three Months Ended*
	Mar. 31, 2012			June 30, 2012			Sept. 30, 2012			Dec. 31, 2012			Mar. 31, 2013			June 30, 2013			Sept. 30, 2013			Dec. 31, 2013
Revenue		100	%		100	%		100	%		100	%		100	%		100	%		100	%		100	%
Expenses:
Cost of revenue		26			22			22			19			21			19			21			15
Sales and marketing		43			40			36			29			37			32			32			25
Technology and development		24			23			27			19			25			27			24			16
General and administrative		22			21			24			20			28			30			38			35

Total expenses		116			106			110			87			111			108			115			91

Income (loss) from operations		(16	)		(6	)		(10	)		13			(11	)		(8	)		(15	)		9
Other (income) expense, net		1			2			1			3			2			2			10			9

Income (loss) before income taxes		(16	)		(8	)		(11	)		11			(13	)		(11	)		(24	)		—
Provision for income taxes		—			—			—			—			—			—			—			—

Net income (loss)		(16	)%		(8	)%		(11	)%		10	%		(13	)%		(11	)%		(25	)%		—	%


	Three Months Ended
	Mar. 31, 2012			June 30 , 2012			Sept. 30, 2012			Dec. 31, 2012			Mar. 31 , 2013			June 30, 2013			Sept. 30, 2013			Dec. 31, 2013
	(in thousands, except for percentages)
Operational Measures:
Managed revenue	$	66,296		$	76,365		$	84,137		$	112,120		$	96,359		$	112,743		$	117,554		$	158,424
Take rate		16.2	%		17.0	%		16.5	%		17.3	%		17.2	%		16.9	%		17.1	%		17.8	%
Financial Measures:
Revenue	$	10,763		$	13,010		$	13,853		$	19,446		$	16,600		$	19,035		$	20,063		$	28,132
Adjusted EBITDA	$	201		$	1,732		$	1,596		$	5,676		$	1,976		$	2,089		$	632		$	6,526


	2014		2015		2016		2017		2018		Thereafter		Total
	(in thousands)
Debt, including interest	$	141	$	141	$	141	$	141	$	3,893	$	—	$	4,457
Capital lease obligations		299		106		—		—		—		—	$	405
Operating lease obligations		3,867		2,026		2,320		110		—		—	$	8,323

Total minimum payments	$	4,307	$	2,273	$	2,461	$	251	$	3,893	$	—	$	13,185


Option Grant Dates	Number of Shares Subject to Options Granted		Exercise Price Per Share			Common Stock Fair Value Per Share at Grant Date
	(in thousands)
December 13, 2012		242	$	4.70		$	4.70
February 22, 2013		2,197	$	7.80	*	$	7.80
April 24, 2013		317	$	7.80		$	7.80
June 7, 2013		560	$	8.30		$	8.30
July 24, 2013		700	$	9.80		$	9.80
October 30, 2013		525	$	11.84		$	11.84
March 3, 2014		500	$	16.22		$	16.22