Google Docs has stood the test of time since its launch a few years ago. Several other similar services have been created since then but nothing can be compared to what Google Docs...
#2: The little time it takes to learn a few shortcuts will pay off.
#11: Comments are the very best feature for providing what I'd call "peer editing without meddling." Students are most often asked to co-coach, not co-author an essay.
Via Jon Samuelson