I watched the preview video about Google Wave, and it looks truly wonderful. It is to be mostly open sourced, and has an API on which third parties can build gadgets - like Google Maps but more so.

For many purposes it may be an up to date replacement for email. Think of the sharing capability of Google Docs, but with character by character interactivity between all participants, real time translation, hierarchy of waves in waves, multi media, realtime translation as messages are typed...

I hope they give me an invite code for the beta test version.

Google Wave could turn out to be very interesting. Email, blog, chat, shared documents, and other stuff, all in one pair of trousers. I want to play with it!