google knows a lot about us

• look at the dashboard . You’ll have to sign in to use it. Go through each service to make sure it’s up to date. On the right columns are links for managing your settings and profiles.
• If you’ve enabled a feature called Web History , check the lists of past searches and delete any you don’t want Google to remember.
• Next, check out Google's Ads Preferences manager. That page reflects what Google thinks it knows about you when you’re not signed in. You can remove or edit categories of interests.
  If you don’t like targeted ads, you can throw Google off by adding a bunch of fake interests. Or simply turn it off by hitting the “Opt out” link and button. You’ll still get ads, just not targeted ones. The page might give you a few chuckles, as Google’s guess of your age and gender is often wrong.
  The Dashboard is tied to your Google account, while the ad manager is specific to your browser, so you’ll have to do this with each browser on each computer or mobile device you use.
  
  
  Read more: http://techland.time.com/2012/03/15/review-5-ways-to-control-your-privacy-on-google/2/#ixzz1pGd1ObWI