We do not store any of your personal information in our servers. As a matter of fact, this app doesn't even have servers to store data on, so no worries there! And since we don't have your info, we can never share it with 3rd parties. (and we wouldn't even if we were able to)
You have the option to sign in with your Facebook account. This is simply to allow you a more personalized experience in the app. It is by no means necessary to enjoy the game. That's all the information is used for. Nothing else.