I think there's room for a lot more innovation in this area. I'm working on some open source code for doing Wave-like stuff in a way that will be easy for people to integrate with other projects. Have you ever tried to edit a wiki page, only to discover that somebody else was editing it and had acquired a lock on the whole page? There's no reason why you shouldn't be able to both edit it, Etherpad-style. Or rather, the reason is that making something like that is hard. But it shouldn't have to be. I hope to have something release-worthy in about a month; right now I've got a distributed text editor prototype that looks like a cross between Etherpad and Notepad. It works, but the code needs an overhaul.
Another problem with Google Wave is that it's inherently centralized. They transform the insert/delete operations so they can be applied out of order and still converge on the same document state. Unfortunately, the method they use for this requires a central server to maintain causal ordering of the operations. There are ways of doing this that don't require a central server, which could be handy.
Another problem with Google Wave is that it's inherently centralized. They transform the insert/delete operations so they can be applied out of order and still converge on the same document state. Unfortunately, the method they use for this requires a central server to maintain causal ordering of the operations. There are ways of doing this that don't require a central server, which could be handy.