Paul Graham is an investor in Stypi, another collaborative editor
similar to Etherpad.
At his behest they added a feature where you can not only replay the
edits, but you can see which edits are ultimately deleted in yellow.
http://www.stypi.com/hacks/13sentences
Just an interesting idea, I thought.
--
Neil Kandalgaonkar ( ) <neilk(a)wikimedia.org>