Relationships, between both people and things, are the root of a user’s social graph. The links in this graph are a rich source of information about a person—his hobbies, preferences, purchasing habits, and many other details that an application developer can use to build a user experience geared specifically to an individual.
A relevant social graph is an application developer’s single most important tool. It is the means by which you engage a new, relevant user base, grow your social application’s audience, and target a set of users based on their social profile details and preferences.
This chapter explores some of the concepts behind the social graph, how you can manipulate it, and how you can extend the social links between users with entity objects that they may interact with. We’ll conclude with an exploration of the Facebook social graph, which is a practical implementation of the graph concepts covered in this chapter, and the OpenLike widget, which can help you promote your product to multiple sources in one easy step.