Dan Connolly's tinkering lab notebook

Ray Ozzie's take on diff/sync

Shortly after I started at Microsoft, I had the opportunity to meet with the people behind Exchange, Outlook, MSN, Windows Mobile, Messenger, Communicator, and more. We brainstormed about this “meshed world” and how we might best serve it - a world where each of these products and others’ products could both manage these objects and synchronize each others’ changes. -- Ray Ozzie
The model behind SSE is pretty straightforward; to sychronize data across multiple sources, each end point provides a feed and the subscribes to the feeds provided by the other end point(s). -- Dare

Seems a lot like the Peer-peer update and sync section of the RDF Delta paper.