Sad news for the handful of us who actually used (or tried to use) Google Wave. It's going away.
This is an example of typical Google, IMO. Strong technology with weak marketing. I don't believe they made it compelling enough for people to use. From an engineering standpoint it was a great tool that could be used for many different things. The questions that people had were along the lines of, "Why should I use Google Wave when I already use <tool or group of tools> to accomplish the same thing? What makes it better?"
Bottom line is that its flexibility was its strength, but flexibility was seen as lack of focus which led to it being underutilized. And much like any non-Facebook social networking site, if the people you want to collaborate with aren't a part of the community, you're pretty much sitting home alone on Saturday night.
Farewell, Wave! We hardly knew you. :(
Official Google Blog: Update on Google Wave