Google is notified whenever you visit one of the more than 25 percent of sites on the web that include Google widgets. 
Turn off the flow of your data to them!
Google Disconnect blocks traffic from third-party sites to Google servers but still lets you access Google services.
Instructions: The add-on displays an icon in the location bar if a page initiates Google requests. You can block or unblock the requests by clicking the icon. Your preference will be remembered the next time you’re on the site.
Note about using Google Disconnect with other filtering add-ons like Adblock Plus: Google Disconnect is compatible with other filtering add-ons, but if you want Google Disconnect to show blocking info, uninstall then reinstall any other filtering add-ons you have (i.e., Google Disconnect must be added first).
1. See http://youtu.be/BK_E3Bjpe0E.