One of the hottest topics in the online world in the last couple of years has been the growth of social networking services such as Facebook and MySpace, as well as the addition of a social element to existing user experiences.  Despite riding several waves of hype, it's now clear that the social networking space will only get hotter in 2008 according to most watchers.  Social software has come fully into its own as of 2008 -- for all appearances permanently -- and understanding the reasons for this rapid rise as well as figuring out how to leverage it best is the job of everyone who wants to make the most of the Web 2.0 era.

Gaining a deeper insight to the social networking phenomenon, now exhibited by the tens of millions of users employing them globally on a daily basis for both personal and businesses uses, currently means understanding the fundamental unit of the social network, also one of the biggest new buzzphrases of the year: the social graph.  Fortunately, that's simple enough despite the term's oblique reference to graph theory, which it is heavily based upon.

Simply put, a social graph is a set of people, referred to as nodes, that are connected together by vertices -- better known as links or connections -- that reflect their social relationships.  You can see a conceptual social graph above, showing the typical distinction of social networks to reflect whether a connection with another person is direct or indirect.  For example, the popular business social networking service LinkedIn, uses this model and sorts a member's social graph into different degrees of separation, which you can see a typical example of below and taken from my LinkedIn profile: