The Social Design Guidelines helps you understand why you should build great social experiences as well as how to use Facebook Platform effectively to create them. Social design is a product strategy that builds upon users’ trusted communities, encourages conversation between them and ultimately creates a stronger sense of identity for everyone.
Social Plugins enable you to provide engaging social experiences to your users with just a line of HTML. Because the plugins are served by Facebook, the content is personalized to the viewer whether or not they have signed into your site.
Open Graph Protocol
The Open Graph protocol enables you to integrate your pages into the social graph. These pages gain the functionality of other graph objects including profile links and stream updates for connected users.
Facebook Platform lets you integrate with social channels such as News Feed and Requests to help you drive growth and engagement with your app, site or content.
Facebook authentication enables your app to interact with the Graph API on behalf of Facebook users and provides a powerful single-sign on mechanism across Web, mobile, and desktop apps.
The Graph API is the core of Facebook Platform, enabling you to read and write data to Facebook. It provides a simple and consistent view of the social graph, uniformly representing objects (like people, photos, events, and pages) and the connections between them (friendships, likes, and photo tags).