I've seen this happen with small communities. The Clock Crew, particularly, has had a number of sites for the same community since 2001. At this point it's pretty much just a bunch of old regulars hanging out on the last site that was left up and a couple of chat rooms, but when things were moving along you might even have two or more significantly active sites at a time. Sometimes you've got to change sites and the guy who owns the old domain disappeared for a few years so you register under something else. There was a while, though, where we had one site on one server and it changed hands several times. We never really had a system for it, though. A site would go down or people would get banned or get sick of the current staff and branch off or whatever. Eventually we got democracy and things honestly kind of stagnated, but that was a bit of a different situation and I think it'd work better for something like Hubski.
Whether that's what the Hubski admins want to do with this or not is a different question.
It'd definitely be cool to have something with a sort of decentralized ownership system ensuring that the best interests of the users would always be served regardless of economic incentives placed on possible future management a decade or whatever down the road when they go into something else.