Well if you ask Apple or Google they'll just say remove the icon completely. Autosave it. That's what happens in Google Docs and iOS + OS X.

It's crazy that we have all this hard drive space and processing power and yet if you forgot to save and the power's out you can lose hours of work. Won't happen to any of Hackernews readers, but probably have bitten my less tech savy friends and family a few times.