You can do sync the Right Way, but it's non-trivial. Programs like Google Docs and Etherpad do really good sync for text documents, because they've put serious

You can do sync the Right Way, but it's non-trivial. Programs like Google Docs and Etherpad do really good sync for text documents, because they've put serious mental effort into figuring out how to get sync to work correctly under (almost) all possible circumstances. If ten people make conflicting edits to a single region of the document and then sync, their documents will provably reach a consistent and reasonable state. Many of the same methods can be applied to other types of synchronization, but it's more effort than most people can spare when they're in a hurry to get something released.