Facebook collects huge amounts of data about its users. As if this weren't bad enough, we know that the social media company also gives out some of this information to third parties.
These third parties are generally app providers and game developers who also use Facebook's platform. If you use Facebook for any of your apps, you should make sure to regularly check what the apps' privacy settings are.
Under "Apps and Websites", you can check and edit the settings
of the websites and apps you have used via Facebook. You can then see if these third party services are able to access your contact list or any other private information.
If you see that third parties are able to access anything you don't want them to, you can turn off
Facebook's integration to the services.
To do this, go from "Settings" to "Apps and Websites" to "Apps, Websites and Games", where you can click on "Turn off". – dpa