Facebook provides a rich set of developer tools for adding 'apps' and joining the Open Graph. To end users, FB is a fun way to stay in touch with friends, make new acquaintances, and generally waste time at work. To advertisers, FB represents unprecedented opportunities for data mining and highly targeted marketing. To developers, it just might be possible to earn a living writing FB apps or accessing the massive volumes of data generated by the Open Graph. To IT students, there's software engineering and computer science just waiting to be absorbed.

Facebook servers support the Open Auth 2.0 protocol ³ for connecting users to apps. This protocol uses a third-party server, which may be concomitant with the FB server to provide authentication and authorization services. Three categories of security are defined by Open Auth 2.0: user authentication, app authorization and app authentication. User authentication protocols convince the server that the end-user on the client-side is who they say they are. App authorization allows the end-user to understand what data and capabilities they are providing to an app. App authentication protects the flow of information from the end-user to the app. The Open Auth 2.0 standard is well-understood and available to all developers: it is not proprietary. ²

Numerous high-profile web sites such as the Wall Street Journal and Hulu have already implemented FB Open Graph and the associated Timeline functionality to allow their customers to share online activity with friends. An individual FB subscriber needs only to give permission once in order to let all their FB friends know what they are doing on other Timeline-enables sites. Facebook characterizes this functionality as a "visual living record of his or her life"¹.

According to their free tutorial page, Facebook developers need only follow 6 broad steps to build, test, and publish an Open Graph app⁴:

1. Create an FB app
2. Authenticate Users
3. Define actions, objects, and aggregations
4. Publish the actions for users to access
5. Add one or more social plugins to the FB app
6. Submit the actions for approval by FB

Sources:

1 http://allthingsd.com/20120117/facebook-open-graph-actions-are-coming-this-wednesday/
2 http://developers.facebook.com/docs/opengraph/tutorial/
3 http://tools.ietf.org/pdf/draft-ietf-oauth-v2-12.pdf
4 http://developers.facebook.com/docs/opengraph/tutorial/#plugins