Great article, fascinating. The author mentions that his system doesn't handle rich text, which is fine, but I'd just like to comment on how difficult of a pro

Great article, fascinating. The author mentions that his system doesn't handle rich text, which is fine, but I'd just like to comment on how difficult of a problem handling rich text is. If anyone is interested in having a personal text-only replay editor, check out http://sharejs.org/ http://sharejs.org/ by an ex-Google Wave engineer. As far as handling rich text, I've talked to the original co-founders of Writely (which became Google Docs), and I've also spent a good 8+ months on it as well. There are lots of tradeoffs involved, that diff-patch-match (as mentioned in the article) won't work on. Doc's ultimately expresses styles as applied ranges, rather than actual markup. Point being, Google keeping every keystroke you've made is absolutely necessary for realtime collaborative writing.