ZDNet interviews Ray Ozzie on the Microsoft - Groove deal...2 good questions asked, and more:

Why did you sell Groove to Microsoft?
Ozzie: From my standpoint, I build software to have a big impact on customers--that's the point of all this. Looking at my past, I was really happy when Notes was able to scale up because of pouring in resources of a larger company (IBM).

In the case of Groove, Microsoft's position across a number of markets--enterprise, government and particularly small business--there's a lot of opportunity we never could have achieved.

Can you give me an idea of what a more peer-to-peer, savvy operating system might do?
Ozzie: Let me do that by a simple example. One of the functions of the current Groove offerings is a thing we refer to is as Groove Folder Synchronization. Right from the Windows Explorer on any folder, you can just right-click on it, and it turns that folder into a synchronized…workspace, where multiple people can work from a folder on your computer to a folder on their computer.

From the user's perspective, that's integrated into the operating system. And that's natural for people. I can't comment on where things will go in the future, but from a user's perspective how these technologies (are) applied at the operating system can be very useful.