New Google Dashboard lets you manage privacy data.

Google unveiled today a new service called Google Dashboard. The site tells you what data Google collects about you, and lets you "manage" that data. 

Check it out. Go to Google.com, and choose "Google account settings" from the Settings menu in the upper right corner of the page. Under "Personal settings at the top, find the "Dashboard" item and click "View data stored with this account." 

Once you're in, you can go through each of the Google services you've signed up for and tweak the settings according to your preferences.