The problem with DMOZ is the corruption of the moderators. This is also becoming apparent in some of the other large community moderated platforms. The final frontier, in essence, is a crowd based decentralized platform for all things social.
With crowdsourcing, I think you get to a point where content coming in becomes normalized (see reddit), and people start migrating away from that community in search of more variety. I would also like to point out the boston bombings fiasco as an example that internet crowdsourcing (read as angry enabled mob) can be silly if not dangerous.
Have there been any studies on how a flat community behaves on the internet?