Some have realised how much AOL knows about us.. how much do you think Google knows?
Yes, Google... their data collection is far more extensive than the AOL incident, which was restricted to actual subscribers. Yes, I know, Google are said to be the "good guys"... but that's today, under the current management. Can you guarantee the future? Do you know how long Google saves its data for? When is it deleted? Is it deleted at all?
Let's have a look at this article about the AOL Search Data released to the public (accidentally).
http://news.com.com/AOLs+disturbing+glimpse+into+users+lives/2100-1030_3-6103098.html
Check out the (very basic) data extrapolation and the assumptions that can be, and are, made according to search phrases used. Are you nevous yet?
Do you believe you've anonymous because you're just some person on the internet with no "membership" with Google similar to AOL subcribers? Lets look at what is collected.
http://www.google.com.au/privacy_faq.html#serverlogs
Don't be too reassured by that "your IP address may change" comment... do you have an always on connection? ADSL? DSL? Realistically, your IP address may not change, or may change rarely, and even if it did change, your ISP will know who used what IP address, and when.