It looks to me like his scheme would remove the real-time requirement. With Google Docs you'll get unresolvable conflicts when one of the users is editing offli

It looks to me like his scheme would remove the real-time requirement. With Google Docs you'll get unresolvable conflicts when one of the users is editing offline or from a slow network. Recording edits in the described way enables asynchronous conflict resolution, and changes don't have to be submitted in real-time for everyone to get the same document.