Facebook Login makes it easy to connect with users on your app or website. You can use several methods in the JavaScript or mobile SDKs to speed up the registration process and build a functional system in minutes.
Email is a protected property and must be specifically asked for and granted.
Extended Permissions give access to more sensitive info and the ability to publish and delete data
Non-optional permissions for access to a user's data and that of their friends.
Open Graph permissions allow your app to publish actions to the Open Graph and also to retrieve actions published by other apps.
Permissions related to management of Facebook Pages.
The public profile and friend list is the basic information available to an app. All other permissions and content must be explicitly asked for.
For certain types of apps, a signed request is passed to the app which contains some additional fields of information.