This is cool. I can see this really catching on as they have ticked a lot of the boxes that are necessary these days – especially making it open source and making it interoperable with other systems based on Wave (federation). This could be a very strong platform to build upon, and could be invisible in the same way that the Twitter website is to those people using a Twiter client.
Most importantly, it could make working (and playing) a lot more straight forward and flexible. People will be able to see the advantages, even if all the possibilities are not immediately clear.