Gephi is an open-source software for visualizing and analyzing large networks graphs. Gephi uses a 3D render engine to display graphs in real-time and speed up the exploration. Use Gephi to explore, analyse, spatialise, filter, cluterize, manipulate and export all types of graphs.
Brad Fitzpatrick recently wrote an elegant and important post about the Social Graph, a term used by Facebook to describe their social network. In his post, Fitzpatrick defines "social graph" as "the global mapping of everybody and how they're related". He went on to outline the problems with it, as well as a broad set of goals going forward. One problem is that currently you need to have different logins for different social networks. Another issue is portability and ownership of an individual's information, explicitly and implicitly revealed while using social networks. As was recently asserted in the Social...
J. Yang, and J. Leskovec. Proceedings of the Sixth ACM International Conference on Web Search and Data Mining, page 587--596. New York, NY, USA, ACM, (2013)