Julia Angwin, The Wall Street Journal, Jan. 25, 2012
From the article: "In a move that could make it harder for Google users to remain anonymous, Google Inc. said it would start combining nearly all the information it has on its users. This could mean, for instance, that when users search via Google, the company will use their activities on sister sites like Gmail and YouTube to influence those users' search results. Google hasn't done that before. Google traditionally hasn't had the same amount of personal data about its users, and has kept much of its personal data separate. But as Facebook gears up for its planned initial public offering this spring, Google has amped up the competition." Read more (subscription may be required)
See Also
Google Announces Privacy Changes Across Products; Users Can’t Opt Out
Cecilia Kang, The Washington Post, Jan. 24, 2012