Just learned about this from Daring Fireball:

http://googleblog.blogspot.com/2010/08/update-on-google-wave.html

We don’t plan to continue developing Wave as a standalone product, but we will maintain the site at least through the end of the year and extend the technology for use in other Google projects.

My colleagues and I have found Wave to be a useful collaboration tool. Looks like we’ll turn to Google Docs as our basic collaboratory.