For the Enterprise 2.0 Proposal, our group has been using Google Groups to coordinate tasks, meetings and information. We’ve also got a Google Doc going to build the actual report. Combining Google Groups and Docs provides one location for discussion, planning and comments, and a separate place to construct the report. Some of the features I’ve found most useful in Google Groups is the mailing list facility to contact all group members. The messages are also stored on the group, which is great for referencing the conversation later.

Image of the front page of our Google Groups page.
I can see some of this functionality being very useful for geographically separated businesses. The usual issue of control over the storage of the data applies, but for travel planning, recording meeting minutes or project groups, Google Groups might be just the thing to keep organised.