@dancohen I linked to this the other day but only managed to read it all the way through last night.
I think there could be some useful applications for those Micro.bloggers who want to develop interest-based subcommunities tangential to M.b. I really like the “neighborhood” metaphor.
And I agree enthusiastically with his idea that certain communities should, by virtue of their values, be actively repulsive to some people. Nothing is for everyone.
I think @macgenie might be interested in what he says about community management.