Looks like some folks are finally beginning to bring the brilliant ideas in BFS to other platforms. Beos had the ability to track your work like this from day one, although the addition of Rendezvous to make it work across multiple computers is novel. I wonder if BFS guru Dominic Giampaolo (didn't have to spellcheck his name thank you very much!) will fold this functionality into OS X since he works in the Apple file system group.