For now they just hacked together something custom for me. However, Etherpad saves every keystroke, so once they enable this for everyone, you'll be able to replay stuff you wrote with it.
Incredible. I was talking about my teacher about how a transition away from paper to tech is great and all but we have lost the sense of keeping drafts. Drafts have a very high value. I don't know how you are connected with the folks @ Etherpad but if there is anyway I can help, let me know.
How do you get the play back link though?