Facebook profiles have become the de-facto identities of people across the internet. This is thanks, in large part, to Login With Facebook, the social network's universal login API, which allows ...

Facebook lets you choose which pieces of information, aside from your public profile, to share with third-party apps and sites you sign into using your Facebook login.

Facebook allows you to login from multiple devices, making it easy to forget exactly where you're signed in. Here's how to see what's logged in.