They know where you live...
Well, not exactly. But if you've ever wondered just how much information about you your searching patterns can yield, this article from Wired News may be enlightening. Cookies certainly offer some details about you, but registering for a site like My Yahoo! gives much more information to their parent sites. The article offers links to the privacy policies of some major search engines (which I had never bothered to look at before), and it also offers some tips to help you maintain at least some anonymity on the web. Of special interest to me, as I just signed up for one, it offers some strong concerns about Google Gmail. All in all, an interesting read.