We often think of communities as organic creatures, which come into existence and grow on their own. However, the truth is they are fragile blossoms. Although many communities surely germinate and bloom on their own, purposefully creating communities can take a tremendous amount of hard work, and one factor their success ultimately depends upon is their numbers. If a community is too small you'll often have insufficient critical mass to sustain it.

Last May I did an abbreviated version of my Dunbar Number talk at MeshForum 2006. A MP3 podcast of that talk is now available at IT Conversations  or can be downloaded here (10mb). If you'd like to follow along, here is a pdf copy of my presentation sides (10mb). Biggest addition to what I've written about before is some discussion about different kinds of social software and what what size groups they seem to be appropriate for.

I will be speaking next Tuesday (July 11th) at the monthly meeting of BayCHI, the San Francisco Bay Area Chapter of ACM SIGCHI (Computer Human Interface Special Interest Group), along with Michael H. Goldhaber. The synopsis of my topic is: The Dunbar Number, Unstructured Trust, and Why Groups Don't Scale We are relying increasingly on internet-mediated social software tools for our day-to-day interaction with other people. To design this type of software, we must better understand the psychology and social dynamics of individuals in groups.