Sam Ruby describes some of the currently popular techniques used to promote collaboration and group forming via weblogs.[1]
Ben Hammersley put together some information on TrackBack and its variants.[2]
Urs Gehrig has many more blogs on Weblogs.[3]
[1] http://www.intertwingly.net/stories/2003/01/17/cohesion.html
[2] http://www.benhammersley.com/archives/003862.html
[3] http://www.circle.ch/blog/c12.html
Sandro Groganz 