InformationWeek
http://www.informationweek.com/blog/main/archives/2008/04/google_rewows_i.html
The continued ability of Google, not to mention AOL, Microsoft, and Yahoo, to use consumer behavior to improve ad quality depends on the willingness of consumers to accept behavioral tracking. And at present, the signs are not good. A study published last October by the Samuelson Clinic and the Annenberg Public Policy Center found that most consumers believe that privacy policies at Web sites prohibit current online advertising practices.