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).
I did not have much time to use digging out Google Wave. Just used it for twenty to thirty minutes. I think it is a nice JavaScript application, in the sense that explores JavaScript, explores asynchronous calls, and real time. But I can not find any other relevant application of it on my everyday life. I do not think it is useful for writing documents cooperatively (it is too much confusion to do so in a thread like approach), I do not think it gets anything new to common forum applications (only the JavaScript thing, probably) and do not think it is better than common IM for user communication. Probably it can be good to record a discussion on some sort of topic, like a forum, but in a faster way. But I am not sure.
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.