Yup!

I think the fact that the idea has been tried so many times though, its doomed to succeed one day ;) There's no doubt of the value it would it would bring if it did take off; usually though after a spectacular release it just dies.

Moderation, timing, and marketing/presentation are the main ones that I can think of based on the predecessors that I have seen (Dissenter, Relay Chat, hypothes.is, etc). I'd love to hear your takes on what other reasons could be or what the biggest ones are.

I actually haven't heard of web tribes though, so I'll read up on it.