GOODWILL AND INTANGIBLE ASSETS (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Goodwill, Impaired, Accumulated Impairment Loss [Abstract]
Goodwill	$ 759,033	$ 505,218	$ 479,123
Accumulated impairment losses	(322,000)	(322,000)	(322,000)
Goodwill	437,033	183,218	157,123
Goodwill [Roll Forward]
Balance at beginning of period	183,218	157,123
Foreign currency translation adjustments	(419)	980
Tax adjustments	(9)
Acquisition	254,243	25,115
Balance at end of period	437,033	183,218	157,123
Impairment	0	0	5,500
Goodwill, Percentage Estimated Fair Values Exceeded Carrying Values By	44.00%
Tax deductible goodwill	46,555	46,900
Technology [Member]
Goodwill, Impaired, Accumulated Impairment Loss [Abstract]
Goodwill	0
Goodwill [Roll Forward]
Balance at end of period	0
Affiliate Marketing [Member]
Goodwill, Impaired, Accumulated Impairment Loss [Abstract]
Goodwill	30,363	30,441	30,177
Accumulated impairment losses	0	0	0
Goodwill	30,363	30,441
Goodwill [Roll Forward]
Balance at beginning of period	30,441	30,177
Foreign currency translation adjustments	(78)	264
Tax adjustments	0
Acquisition	0	0
Balance at end of period	30,363	30,441
Media [Member]
Goodwill, Impaired, Accumulated Impairment Loss [Abstract]
Goodwill	264,369	217,914	217,801
Accumulated impairment losses	(112,000)	(112,000)	(112,000)
Goodwill	152,369	105,914
Goodwill [Roll Forward]
Balance at beginning of period	105,914	105,801
Foreign currency translation adjustments	(33)	113
Tax adjustments	(9)
Acquisition	46,497	0
Balance at end of period	152,369	105,914
Owned and Operated Websites [Member]
Goodwill, Impaired, Accumulated Impairment Loss [Abstract]
Goodwill	256,555	256,863	231,145
Accumulated impairment losses	(210,000)	(210,000)	(210,000)
Goodwill	46,555	46,863
Goodwill [Roll Forward]
Balance at beginning of period	46,863	21,145
Foreign currency translation adjustments	(308)	603
Tax adjustments	0
Acquisition	0	25,115
Balance at end of period	46,555	46,863
Dotomi Inc [Member]
Goodwill, Impaired, Accumulated Impairment Loss [Abstract]
Goodwill	207,746	0	0
Accumulated impairment losses	0	0	0
Goodwill	207,746	0
Goodwill [Roll Forward]
Balance at beginning of period	0	0
Foreign currency translation adjustments	0	0
Tax adjustments	0
Acquisition	207,746	0
Balance at end of period	$ 207,746	$ 0