Hooks/callbacks would be helpful. (Like sync starting, sync finishing, maybe conflicts). I'm not sure what what the Bittorrent folks think of this, but it would be really nice if the protocol was specified so people could implement it themselves if they wanted to, without reverse engineering the protocol. (I think this technology could be used quite a bit in the open source world, but they tend to be more accepting of things if there is an open source implementation. I could see cases where people would join a linux distro share, and on release day automatically get the latest images.)
