Imagine a big cast iron pot, throw in Appengine, XMPP, Blogs, Wikis, stir, simmer, and serve.  Wave!  Some particularly interesting bits from the API preview doc:

You define the behavior of your robot by defining the events which you wish your robot to be notified. Wave contacts the robot whenever one of these events occur, such as a change made to a wave in which the robot is a participant.

I spent an absurd amount of time hand crafting an email-bot a few years ago that could respond to my old improv team’s email list with information about our upcoming shows.  It ended up being pretty useful, but took a bunch of time to write.  Anytime an announcement includes robots, I’m hooked.

The Java and Python client libraries allow you to design your robot

Python!  (Note to Google, please rewrite the above to read: The Python and Java client libraries.)

Lastly, there’s a Chess gadget!

Obviously, the real test will be adoption.  I signed up for sandbox access, because it feels like this is the future, and I want to support it.  A slew of my non-technical friends now treat Facebook (nice, but a non-open standard) like it’s email.  As a consultant I’d love to be able to suggest modern collaboration tools that don’t tie you into one particular vendor.  And most importantly, Wave looks like a heck of a lot of fun to play with.  Although I haven’t released anything of any importance on Appengine, I love the concept.  The Appengine deployment process, applied to collaboration, seems like a real win++ to me.  Nice work Googlers.