Hmmm--how about NodeDiff? I'm only being partially facetious here, but if the point is in the differences we might as well have the right tool for the job. Personally I subscribe to Ted Nelson's vision of hyper-documents, all versions, live, on-line, all of the time. For more on that subject see http://www.xanadu.net/

--hsm

"Never try to teach a pig to sing...it wastes your time and it annoys the pig."