Similarity in on-line communities

In two interesting papers, Ludford and others discuss the importance of similarity in on-line communities:

In face-to-face interaction, people become friends with others who have interests and demographics similar to their own. This notion, supported by empirical sociology research, has not yet been widely explored by researchers studying online communication. If the same principles hold in the online world, the results could improve online communication forums. New technology could funnel those with similar (or complementary) interests to places where they could exchange ideas online.

"Studying the Effects of Similarity in Online Task-Focused Interactions", Cosley, D., Ludford P.J., Terveen, L.G., GROUP 2003 conference

"Think Different: Increasing Online Community Participation Using Uniqueness and Group Dissimilarity", Ludford, P.J., Cosley, D., Frankowski, D., Terveen, L.G., Ac, CHI 2004

Why do I blog this? I use this kind of material in a report about on-line communities creation and maintenance I am writing currently.