p2pfoundation has an interesting post about the importance of time as a dimension in social networking technology. My concept of RhNav - RhizomeNavigation includes some of these thoughts...
C. Scholz, M. Atzmueller, and G. Stumme. Proc. Fourth ASE/IEEE International Conference on Social Computing (SocialCom), Boston, MA, USA, IEEE Computer Society, (2012)
B. Pereira Nunes, R. Kawase, S. Dietze, D. Taibi, M. Casanova, and W. Nejdl. Proceedings of the Web of Linked Entities Workshop in conjuction with the 11th International Semantic Web Conference, volume 906 of CEUR-WS.org, page 45--57. (November 2012)