Comment by remus

I think even the idea of merging changes is a step too far for all but the most technical users. Most user's idea of what it should look like start and end at a word-like UI, so having to introduce the idea of merging different copies together and resolving conflicts is too far outside that view. In my opinion this is why Google docs has become popular because it solves that tricky problem of having to think about how your edits interact with someone else's.