Here are some references for work on social networks and related topics;
Dodds, P., Muhamad, R. & Watts, D. (2003). An experimental study of search in global social networks. Science, 301, 827-829. In: Banyard, P. & Grayson, A. (2008). Introducing psychological research. Third edition. New York: Palgrave.
Hussain, Z. & Griffiths, M.D. (2008). Gender Swapping and Socializing in Cyberspace: An Exploratory Study. CyberPsychology & Behavior, 11, (1), 47-53.
Hussain, Z. & Griffiths, M.D. (2009). The Attitudes, Feelings and Experiences of Online Gamers: A Qualitative Analysis. CyberPsychology & Behavior, 12, (6), 747-753.
Madge, C., Meek, J., Wellens, J., Hooley, T. (2009). Facebook, social integration and informal learning at university: It is more for socialising and talking to friends about work than for actually doing work. Learning, Media & Technology, 34, 2, 141-155.
Manago, A.M., Graham, M.B., Greenfield, P.M., Salimkhan, G. (2008). Self-presentation and gender on MySpace. Journal of Applied Developmental Psychology, 29, 6, 446-458.
Pempek, T.A., Yermolayeva, Y.A., Calvert, S.L. (2009). College students’ social networking experiences on facebook. Journal of Applied Developmental Psychology, 30, 3, 227-238.
Travers, J. & Milgram, S. (1969). An experimental study of the small world problem. Sociometry, 32, 425.