Nicholas Christakis: The hidden influence of social networks (TED talk video)

Interesting that he sees networks as a promoter of 'goodness', as no doubt they can be. But biological studies in the evolution of cooperation have also shown that networks can be promotors of group benefits at the (often harsh and violent) expense of 'out groups' - those outside of the networks. His metaphor for networks as an 'endless fabric of humanity' seems a little naive? Perhaps his 'mission' is to extend networks in ways that break through traditional group boundaries?