The government can gain access to Google's data storehouse simply by presenting a valid warrant or subpoena. Under the Patriot Act, Google may not be able to tell users when it hands over their searches or e-mail messages. If the federal government announced plans to directly collect the sort of data Google does, there would be an uproar - in fact there was in 2003, when the Pentagon announced its Total Information Awareness program, which was quickly shut down.
Adam Cohen NYT 28-Nov
S'il n'en faut pas plus pour vous rendre parano (ou simplement vous énerver contre ce qui se passe à l'insu de votre plein gré) vous pouvez toujours utiliser la version expurgée de Google : SCROOGLE (le site renvoie les résultats du moteur Google en virant tous les trackers, soit no cookies, no search-term records, access log deleted after 7 days)