With so many websites to join, users must decide where to invest significant time in adding their same connections over and over. For developers, this means it is difficult to build successful web applications that hinge upon a critical mass of users for content and interaction. With the Social Graph API, developers can now utilize public connections their users have already created in other web services. It makes information about public connections between people easily available and useful.

+ Social Graph API FAQ
+ Something to play with-
Demo Social Graph API - My Connections : Who are you connected to?
Keywords: Google, OpenSocial API, Social Graph API, Google API