Received today the invitation to join Google Wave project. Sincerely, I had no idea about what was Google Wave when I asked a friend for the invitation. But Google has nice projects and I like to know them (and use them when I think they can help on my everyday life).
For now, I think it is a good way to waste memory and CPU cycles. My Firefox (under Mac) did not like much the experience, and we had just 4 simultaneous users.