This add-on will prevent Google from tracking your searches, movements, what websites you visit and what search results you clicked on when you are not logged in a Google services like Gmail, Gdocs, etc.
This add-on is not a complete proxy service. It only sends Google tracking related traffic through the proxy. If you browse a non-Google website traffic will be sent to the internet normally.
Interested users can install this add-on from Mozilla add-on site