bah.. old news.
Ofcourse google is trying to figure out what everyone likes and dislikes. There are HUGE money waiting for anyone who can sell ads that would actualy target someone who might actualy want to buy, unlike now where volume iz da muck.
Just take a look at the cookie-file
www.google.com generates. Take a look at the EXPIRY-DATE... now why would they need that, if not to keep track of you and your searching.