Social graph and beyond

Taking the previous thread forward, presuming we can solve the unique yet common identity problem, how can I use and benefit from my social graph apart from just staying in touch with people and sharing community/work specific knowledge/information.
I reckonOpen Social a project undertaken by Google that involves building "a set of common APIs for building social applications across the web", could be the next big thing.Though the description does not reveal much except that it would enable social networking sites to allow influx and outgo of user and graph centric data.This move makes the possibility of a USN (unified social network) if i may call it,coming into existence look real.Moreover, since data flows two ways on graphs, this could mean that one could relate any piece of data/information on the web to one's social graph.Six degrees !