OTs are the same idea along with a sort of rebase step for replaying changes that come in to get the head to the same point (regardless of the order in which the operations were received).

It seems like a great model, but as I mentioned above, there's surprisingly little code around for you to draw on. I seem to recall reading a conversation from the ShareJS guys (though maybe it was someone else) about how hairy the edge cases can get when you're trying to do it for general data-structures (which was disappointing, because conceptually it seems simple).