When you sign in to Facebook with Boxed In, we store your Facebook User ID. This unique string of characters doesn't personally identify you, but allows us to associate you with high scores and level submissions.
We use the your Facebook User ID to indentify you as a person. This along with the user name you generate in Boxed In allows us to display player high scores in game and on the Boxed In website.
We don't share your information with anyone.