Demo of Janrain Social Login with Progressive Permissioning
Try viewing source in the page to see what's going on here.
This demo shows to use Progressive Permissioning to ask only for a minimal amount of data upon an initial login, then come back later and collect more data at the time it is needed.
For the formal docs on this feature, please see: http://developers.janrain.com/documentation/widgets/social-sign-in-widget/users-guide/progressive-permissioning/
Note that as of this time, Progressive Permissioning only works with Facebook. Therefore it is the only provider listed in this instance of the Social Login widget. The data returned after authenticating in this page will be whatever data is configured to be returned from FB in the Janrain Social Login Dashboard (i.e. progressive permissioning is not yet being used here...that will be shown in the next page...)