DO NOT USE YOUR FACEBOOK ID TO LOG IN TO NON FACEBOOK WEB SITES

These are many apps from Candy Crush and Airbnb to Spotify and Uber that allow users to sign in using their Facebook password. It’s so convenient (only one password to remember!) that many people opt in.
Every third-party app is different in the kinds of data that’s collected. But the important step to remember is to stop and really read through what you’re agreeing to—even if sometimes it’s contained in a lengthy legalese agreement—before casually hitting the “continue” to log in using Facebook button. Typically, these apps want access to names, genders, and locations. But many apps dig deeper into personal preferences and friend networks.

Source: Facebook: What Personal Data It Collects And Shares From Users | Fortune