I just received my google wave invitation. In a nutshell, google wave is a way of collaborating in real-time. Principally, it changes the location of the information exchange from the edges, i.e. the individual user's computers, to making everything happen in a centralized server therefore turning every user's computer in to a thin client.
There are robots, which behave as programmable agents, among many other useful features. I believe this is all best explained by the google wave team themselves. They have released a short 8 minute video, in contrast to the 80 minute one available before!
Enjoy,
Felix
