Google has unveiled yet another cool idea for communication in the cloud. Google wave allows communication across email, blogs, social networks seamlessly. The fact that email being considered as a bulletin board application gives a different face to the traditional email system we have accustomed to until now. Although it is much more than just email and scraps.
And yes, it is Open Source!
Check out the awesome Developer Preview video here http://www.youtube.com/watch?v=v_UyVmITiYQ.