If the web is a "Social" something then this equals Facebook, Xing, Twitter, LinkedIn Google+.
But social could mean….
"see what your friends are searching, buying, watching, liking, saying or doing"
"buy together and recommend
"filtered by who you know"
"what's trending"
"where are my friends right now or where will they be"
Given that a social graph is a digital map that says, "This is who I know." It may reflect people who the user knows in various ways: as family members, work colleagues, peers met at a conference, high school classmates, fellow cycling club members, friend of a friend, etc. Social graphs are mostly created on social networking sites like Facebook and LinkedIn, where users send reciprocal invites to those they know, in order to map out and maintain their social ties.
And an interest graph is a digital map that says, "This is what I like." As Twitter's CEO has remarked, if you see that I follow the San Francisco Giants on Twitter, that doesn't tell you if I know the team's players, but it does tell you a lot about my interest in baseball. Interest graphs are generated by the feeds customers follow (e.g. on Twitter), products they buy (e.g. on Amazon), ratings they create (e.g. on Netflix), searches they run (e.g. on Google), or questions they answer about their tastes (e.g. on services like Hunch).
However where is the value? It has to be in the mashup/ combination of all social data so I can determine who influences you and who you influence – where is your power and how much you are worth to a brand…….