I just tried out Google Docs and noticed they have version control for edits. If you use automatic save mode, every time you do something Google saves it so you can undo to any point in the session.
This is very cool! Does anyone know of an offline office suite that does that? My IDE does, but it's doesn't do Excel.
I wouldn't want to store most data online because then you need to be online to use it. I tried it out setting up the JavaRanch Server Fundraiser book request data (where I need to be online anyway for data collection) and it's a very nice product.