Tips & Tricks
In OS X Lion, Apple introduced some new features for working with files, and a new hidden menu to access them. When you’ve opened a document, move your cursor over its name to bring up a small black arrow just to the right. Click this arrow and you bring up a menu with some of these new options. The most useful are the ability to rename and duplicate files, but you can also lock a file to prevent further editing, change it so that the file is stored in iCloud instead of only on your hard drive (though only in compatible apps), or move the file.
The flashiest feature is the ability to revert to a previous version of a file, though: you can choose an older version from what’s listed in this menu, or click ‘Browse All Versions…’ to enter a Time Machine-like interface, where you can scroll through older versions of that file and compare them to the current one.