So remember those times when you had to kick yourself for forgetting to save your term paper and then the electricity went out or some other catastrophic event took out your computer or laptop? Well, Apple's new Mac OS X Lion is here to save the day. It's added a new Auto Save and Resume feature.
The feature resembles Time Machine but is for each single document. When you close a document there is no "Do you want to save?" because Lion automatically saves it for you.
There's now a "History" option in the middle of the menu bar that pulls down "Lock", "Duplicate", "Revert to Last Opened" and "Browse all Versions." You can revert to a previous version if you don't like what was just saved. You can also select "Lock" if you don't want to auto save.
These versions that you can revert back to, only save each copy's changes, and not the entire document each time. You can also take a manual snapshot of the current status and then page back through different versions.
When you share your document, only the most current version is used. And, its possible to copy content between different versions.