Google Wave is being developed under the leadership of the same brother team that developed Google Maps (Lars Rasmussen and Jens Rasmussen), and basically re-envisions the 35+ year old email concept, from todays perspective -- really a personal social dashboard. 2 years in development using Google Web Toolkit, Google Wave mashes together and federates a huge number of more recent social and collaborative concepts, from email, IM, file and image sharing, document collaboration, wikis, blogging, and more. Say bye to having to manage 35 different social networks! Wave will consolidate them all into a single interface. Along with every other collaboration and social tool you use. Oh, and it's also a protocol -- more on that later.
And it does this in real-time, within a browser. When you add content, the content is immediately available to who-ever you're sharing with, without them having to reload pages. It's just there -- true real-time multi-author document collaboration. And when I say mash, I mean, completely blurs the boundaries between modes of collaboration. An email style Wave can become an IM, and a blog, and a document. Back and forth, whenever you like.
There's new concepts in there too. Real-time, context sensitive spell checking. Type in "I really like been soup" and it knows you meant "I really like bean soup" and corrects it. "Icland is an icland" automatically becomes "Iceland is an island". There's also real-time language translation. The devil will be in the details here, but the demo was very smooth.
The federation is a key concept here as well. Clearly Google will be hosting Wave. But it's open source. You can also host your own Waves on your own server -- Google doesn't get that content. It's also fine grained federation. If you have a Wave hosted on a Google server, but share that out to a federated server, and then decide to make some of the Wave content private, that private content resides only on the federated server -- not at Google. This is all done using the Wave protocol -- again fully open.
Oh, and it's open source. At the moment it's an early developer release. They're opening things up early to get developers working on extensions, using the full API.
Check out the video demonstration -- it's 90 minutes long, but well worth watching.