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...
P. Singer, D. Helic, A. Hotho, and M. Strohmaier. Proceedings of the 24th International Conference on World Wide Web, page 1003--1013. Republic and Canton of Geneva, Switzerland, International World Wide Web Conferences Steering Committee, (2015)
R. Jäschke, and S. Rudolph. Contributions to the 11th International Conference on Formal Concept Analysis, page 19--34. Technische Universität Dresden, (May 2013)
F. Shipman, III, C. Marshall, and M. LeMere. Proceedings of the tenth ACM Conference on Hypertext and hypermedia : returning to our diverse roots: returning to our diverse roots, page 121--130. New York, NY, USA, ACM, (1999)
M. Kitsuregawa, T. Tamura, M. Toyoda, and N. Kaji. Progress in WWW Research and Development, volume 4976 of Lecture Notes in Computer Science, Springer, Berlin/Heidelberg, (2008)
A. Brew, D. Greene, and P. Cunningham. Proceedings of the 19th European Conference on Artificial Intelligence, volume 215 of Frontiers in Artificial Intelligence and Applications, page 145--150. Amsterdam, The Netherlands, The Netherlands, IOS Press, (2010)