Intangible Assets (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 6 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2012
Jun. 30, 2011
Jun. 30, 2011
Sep. 30, 2012
Dec. 31, 2011
Finite-Lived Intangible Assets, Net [Abstract]          
Gross carrying amount $ 272,344     $ 272,344 $ 268,535
Accumulated amortization (183,767)     (183,767) (157,231)
Net 88,577     88,577 111,304
Weighted average useful life       5 years 3 months 18 days 5 years 3 months 18 days
Amortization of intangible assets 9,501 10,828 30,781 31,216  
Service costs [Member]
         
Finite-Lived Intangible Assets, Net [Abstract]          
Amortization of intangible assets 7,556 8,825 24,372 25,261  
Sales and marketing [Member]
         
Finite-Lived Intangible Assets, Net [Abstract]          
Amortization of intangible assets 641 755 2,345 2,004  
Product development [Member]
         
Finite-Lived Intangible Assets, Net [Abstract]          
Amortization of intangible assets 1,068 995 3,275 3,204  
General and administrative [Member]
         
Finite-Lived Intangible Assets, Net [Abstract]          
Amortization of intangible assets 236 253 789 747  
Owned websites names [Member]
         
Finite-Lived Intangible Assets, Net [Abstract]          
Gross carrying amount 44,198     44,198 43,343
Accumulated amortization (39,623)     (39,623) (35,674)
Net 4,575     4,575 7,669
Weighted average useful life       3 years 7 months 6 days 3 years 9 months 18 days
Customer relationships [Member]
         
Finite-Lived Intangible Assets, Net [Abstract]          
Gross carrying amount 27,325     27,325 27,325
Accumulated amortization (22,465)     (22,465) (20,257)
Net 4,860     4,860 7,068
Weighted average useful life       5 years 9 months 18 days 5 years 9 months 18 days
Media content [Member]
         
Finite-Lived Intangible Assets, Net [Abstract]          
Gross carrying amount 133,935     133,935 130,981
Accumulated amortization (72,776)     (72,776) (56,847)
Net 61,159     61,159 74,134
Weighted average useful life       5 years 1 month 6 days 5 years 1 month 6 days
Technology [Member]
         
Finite-Lived Intangible Assets, Net [Abstract]          
Gross carrying amount 38,694     38,694 38,694
Accumulated amortization (27,430)     (27,430) (24,055)
Net 11,264     11,264 14,639
Weighted average useful life       5 years 9 months 18 days 5 years 9 months 18 days
Noncompete agreements [Member]
         
Finite-Lived Intangible Assets, Net [Abstract]          
Gross carrying amount 14,806     14,806 14,806
Accumulated amortization (14,645)     (14,645) (14,513)
Net 161     161 293
Weighted average useful life       3 years 3 months 18 days 3 years 3 months 18 days
Trade names [Member]
         
Finite-Lived Intangible Assets, Net [Abstract]          
Gross carrying amount 11,294     11,294 11,294
Accumulated amortization (5,417)     (5,417) (4,652)
Net 5,877     5,877 6,642
Weighted average useful life       14 years 6 months 14 years 6 months
Content publisher relationships [Member]
         
Finite-Lived Intangible Assets, Net [Abstract]          
Gross carrying amount 2,092     2,092 2,092
Accumulated amortization (1,411)     (1,411) (1,233)
Net $ 681     $ 681 $ 859
Weighted average useful life       5 years 5 years