Google Alarm Firefox add-on is a pretty cool firefox addon which alarms you when your personal information is sent to Google. As you must be knowing its not just Google sites which are sharing your info, other major sites do that as well. So, when you install this plugin and the information sharing happens you will be treated with a alarm(which gets to you after sometime).
The Google Alarm Firefox addon visually & audibly alerts you when your personal information is being sent to Google servers.
Even outside Gmail and YouTube you are constantly sending information to Google through their vast network of tracking bugs: Google Analytics, Google AdSense, YouTube embeds, API calls.. all of this data be used to monitor & track your personal web browsing habits.
Video showing the plugin in action :
You can install the plugin from here.