@a440
Here is what I believe to be true:
Google, plus any number of other companies will have cookies (or whatever) that monitor your searches, what websites you visit, the sort of clothes you might search for as well as your e-mail address and such.
If the company is related to Google, the information is passed on. In other cases, these companies sell the information they've collected to Google, (making money off you, without your permission) so Google can provide relevant advertising and make money off you. This goes on without your consent. I would say that whilst you cannot search this information, the internet has a pretty good idea of who you are. Ever wonder why you still get those "Online Pharmacy" e-mails when you never post your address? I believe this to be the reason: You filling in forms on various sites, then the Google or whoever gets this info and sells it...
Its disappointing no-one has actually sued Google or any number of other companies for earning money off them, or invading their privacy. I saw a YouTube video once that explained that after just a simple google search, and a few clicks, you have anywhere up to 20+ different companies who know you've searched for what you searched for (This was at school, by the way).
That is why I installed DoNotTrackMe. When it is disabled, I still do not see any ads, so I might have to alter Firefox's settings...