SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* Charles River Partnership XIII, LP (Last) (First) (Middle) ONE BROADWAY 15TH FLOOR (Street) CAMBRIDGE MA 02142 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Millennial Media Inc. [ MM ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 03/05/2013
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	03/05/2013		J(1)		500,000(1)	D	$0	8,172,214(2)	D(3)(4)
Common Stock	03/06/2013		S(5)		14,034	D	$8.1913	8,158,180(6)	D(4)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person* Charles River Partnership XIII, LP (Last) (First) (Middle) ONE BROADWAY 15TH FLOOR (Street) CAMBRIDGE MA 02142 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Charles River Friends XIII-A LP (Last) (First) (Middle) ONE BROADWAY 15TH FLOOR (Street) CAMBRIDGE MA 02142 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Charles River XIII GP, LP (Last) (First) (Middle) ONE BROADWAY 15TH FLOOR (Street) CAMBRIDGE MA 02142 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Charles River XIII GP, LLC (Last) (First) (Middle) ONE BROADWAY 15TH FLOOR (Street) CAMBRIDGE MA 02142 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. Represents a pro rata distribution for no consideration to the partners of Charles River Partnership XIII, LP ("CRP XIII LP"). Of the 500,000 shares distributed, 8,021 shares were distributed to Charles River XIII GP, LP ("CR XIII GP LP"), which is the general partner of CRP XIII LP, and these shares were then further distributed on a pro rata basis for no consideration to the partners of CR XIII GP LP. Of the 8,021 shares distributed by CR XIII GP LP, 9 shares were received by Charles River XIII GP, LLC ("CR XIII GP LLC") which is the general partner of CR XIII GP, LP. CR XIII GP LLC then distributed these 9 shares on a pro rata basis for no consideration to its members.

2. The number of shares owned after the distribution includes 7,935,447 shares held by CRP XIII LP and 236,767 shares held by Charles River Friends XIII-A, LP ("CRF XIII-A").

3. The pro rata distribution from CRP XIII LP to its partners, and from one partner to another partner as general partner or member of the distributing partner, reflects a change in form of beneficial ownership only of the ultimate partner, and does not reflect a change in such ultimate partner's pecuniary interest in the securities reported herein.

4. CR XIII GP LP is the general partner of CRP XIII LP. CR XIII GP LLC is the general partner of both CRF XIII-A and CR XIII GP, LP. Each reporting person may be deemed to beneficially own the reported securities, but each disclaims beneficial ownership of such reported securities except to the extent of its pecuniary interest therein. The filing of this statement by any reporting person shall not be deemed an admission that such person is, for purposes of Section 16 of the Securities Exchange Act of 1934 or otherwise, the beneficial owner of any equity securities covered by this statement.

5. Sale by CRF XIII-A.

6. The number of shares owned after the sale includes 7,935,447 shares held by CRP XIII LP and 222,733 shares held by CRF XIII-A.

	/s/ Sarah Reed, as Attorney-in-Fact for Charles River Partnership XIII, LP	03/07/2013
	/s/ Sarah Reed, as Attorney-in-Fact for Charles River Friends XIII-A, LP	03/07/2013
	/s/ Sarah Reed, as Attorney-in-Fact for Charles River XIII GP, LP	03/07/2013
	/s/ Sarah Reed, as Attorney-in-Fact for Charles River XIII GP, LLC	03/07/2013
	** Signature of Reporting Person	Date
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