Condensed Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Revenues:
Subscription revenues	$ 98,093	$ 74,239	$ 279,983	$ 204,343
Product and other revenues	5,008	5,076	15,454	13,853
Total revenues	103,101	79,315	295,437	218,196
Costs of revenues:
Cost of subscription revenues	15,292	11,267	43,290	33,996
Cost of product and other revenues	1,558	1,155	5,227	3,929
Total cost of revenues	16,850	12,422	48,517	37,925
Gross profit	86,251	66,893	246,920	180,271
Operating expenses:
Technology and development	14,773	10,528	42,683	30,447
Marketing and advertising	30,266	24,125	94,324	71,061
General and administrative	9,753	9,141	29,221	24,915
Amortization of acquired intangible assets	4,304	3,791	12,871	11,149
Total operating expenses	59,096	47,585	179,099	137,572
Income from operations	27,155	19,308	67,821	42,699
Interest and other expense, net	(393)	(1,585)	(929)	(4,158)
Income before income taxes	26,762	17,723	66,892	38,541
Income tax expense	(7,711)	(5,914)	(22,313)	(14,247)
Net income	$ 19,051	$ 11,809	$ 44,579	$ 24,294
Net income per common share:
Basic	$ 0.43	$ 0.27	$ 0.99	$ 0.56
Diluted	$ 0.40	$ 0.24	$ 0.90	$ 0.50
Weighted average common shares outstanding
Basic	44,670	43,984	45,209	43,075
Diluted	48,173	48,774	49,436	48,186