The basic complaint is that social sites grow into mobs. The solution is rather obviously: halt growth. You have to limit the number of active users to some v

The basic complaint is that social sites grow into mobs. The solution is rather obviously: halt growth. You have to limit the number of active users to some vaguely Dunbar-ish number or you inevitably wind up with a lowest common denominator mob. Metafilter did this, right? For a couple years they said "No new accounts." I think scaling a social site to a very large number of members without deteriorating badly is impossible. It's a matter of human nature and mobs.