Google pulled the plug on Wave a few weeks ago. This is an unfortunate development for us as we found Wave to be quite useful. We have used it to successfully collaborate on a couple of projects as our designer lives a few hundred kilometres away from where we are. The ability to login at any time and view documents, graphics and other work; catch up on the dialogue and add to it was very useful. The real time aspect of it was also beneficial. Having all the tools in one place worked very well for us.
You may have heard about Google Wave. It's a new technology being developed by Google. Google describes it as: