I have been using Groove (http://www.groove.net) for a little while. I think that it is the third and essential piece of information technology needed for cross-organizational communities of learning. (not counting e-mail which I take for granted). The first is Weblogs--the place to hold context, to get to know people. The second is something like WebCrossings--a place to have and keep discussions and documents by topic. And third, Groove for private, secure, multi-participant collaborations.
Here is a link to a web post that describes how I think Groove fits in. I like the idea "center to edge to center". We get what we know from the center, we take it off and work on it and we return it with our innovations and learnings to the center for others to then elaborate and improve upon. So Paresh Suthar, in his own words http://radio.weblogs.com/0111019/2003/05/08.html