Patrick Logan picks up my bait about Groove and Croquet. Which, on the surface, are very different: Groove is some combination of document- and forms-based workspaces, presence and messaging, wheras Croquet has that white rabbit, a waterfall, a cool flag, and things that look like mirrors but behave like doors.

Underneath though, they solve the coordinated distributed persistent objects problem in very similar ways. Groove's "dynamics" is like IDispatch plus a message queue: commands against objects ("engines", in the parlance) are distributed to peers who share the model. There's no shared data, only a coordinated transaction history. And Croquet's "TeaTime" does approximately the same thing, only with Smalltalk method dispatch instead of COM method dispatch.

Anyway, that's an astronaut-view, and bears little relation to the real world. In the daily life of an office worker, I just hope that grooviness -- transparent under-the covers no-effort secure robust synchronization of workspaces, their structures and their contents -- will become something you can take for granted.