Explains what social login is, then further explains how you can implement it.
Articles
Social Login Overview
Janrain’s Social Login offering supports convenient and secure sign-in, authenticated by a long and growing list of identity providers.
Implementing Social Login
A Social Login application is needed for implementing both social login and social sharing. It can be created in Janrain's Engage Dashboard using these instructions.
Single Sign-On with Social Login
By default, Single Sign-on authenticates all users who visit a member site who have an active SSO session open.