If you have a Facebook account you might want to look into the “instant personalization” that has started.
The new change shares your information with Facebook and non Facebook sites such as Bing, Trip Advisor etc…
You can read about this new feature here:http://www.facebook.com/instantpersonalization/
If you decide you do not want to allow instant personalization on your account- it is very simple to remove:
Go to Account on the top right hand side.
Go to Privacy Settings
Go to Apps and Websites and Edit Your Settings
Go to Select edit settings on Instant Personalization
UNCHECK the enable option.
If your friends do not do this, they will be sharing your information as well.