I have now been for about a week on the "Wave", Google's proposal for the future of communication on the Internet. My overall impression after that week: It's not for me (at the moment?).
Thanks to Daniel E. Renfer I got an invite which was activated after only a few days. The first thing you hear about Google's Wave is that it is slow. I can endorse that statement. Using the web interface on my poor little netbook is a pain. Loading a new wave takes at least 10 seconds, jumping to the next unread item takes the same. I have taken to writing longer texts in Emacs and then pasting it in one go into the Wave — pasting is fast, but the one-keystroke-after-the-other display updates are painfully slow. I accept that much of this has to do with my "underpowered" netbook that isn't exactly beefy. But it works fine with most other web sites (as long as you don't want to watch videos); it's not snappy, but it's usable — except with Google's Wave.
A less fancy client might be a good idea. I really don't need all these animations and pointy-clicky interface. Somebody is working on an Emacs interface already though so possibly there is light at the end of this tunnel.
There is also the problem of content — Google strictly controls the number of people admitted to this beta product so it's not likely many of your friends and colleagues will have an account. At the same time it's a pain trying to find some interesting discussions (hint: add "with:public" to the search to find public discussions) and once you find something interesting you'll find that any discussion soon dissolves into a rapid sequence of newbies posting /"Hi I am on the Wave as well"/ — this is new territory and people still need to learn proper protocol to keep waves tidy and interesting. For the moment I have little reason to sign in to Wave, there's just nothing there to go to.
On the plus side, I did get a couple of invites fairly soon after joining, so by now there are more people from my social vicinity signed up. None of those are exactly active though and for interactive communication IM style you'll need to catch your peers online (signed into Wave that is) — that doesn't happen often for me, I guess it's yet another thing you have to be logged in to and keep monitoring, so people don't bother (at the moment at least).
So, don't give up on Google Wave just yet, but for the moment I am deeply underwhelmed.