For the past week I've been doing the Google Wave dance. First impressions are, it's a really interesting mashup of different messaging/content concepts - Wiki meets IM meets Email threading - but it's way too cluttered. The social web evolution tells us that simpler is better, services tend to be straightforward, simple, uncluttered, fast. Google's own web page was a hit precisely because it was simple, clean and to the point, Twitter and all related services are the same thing. Having a huge chunk of my desktop space occupied by one browser window with a bunch of stuff because that's what it takes to be able to interact with Google Wave is way too intrusive. And of course, the fact that it can literally bring the browser to it's knees tells me that it might be a bit too much for a web app.
I'm looking forward to seeing how it evolves, I'm sure a lot of people are getting ideas for better ways to do it... I've had a bunch already. In the meantime, I'm on it as email@example.com, feel free to add me to waves, I want to see what people are doing with that thing.