Facebook rolls out a new, simpler application authorization process for third-party apps, mandating that apps specify exactly what data they wish to access; "when you log into an app with Facebook account, the app will only be able to access public parts of profile by default. To access private sections, the app has to explicitly ask for your permission."
This new permissions box will pop up whenever you install a new app or first log in to an external website with your Facebook account.
"Now all data that an app wishes to access will be presented in a single dialog box. As usual, app will be able to access data that you've shared with "Everyone". Beyond that, users will be told in plain English exactly what private data they're sharing, which can include things like your Email address, photos, and videos."