Time Machine is a great backup application that has been included in OS X since the release of Leopard. My Time Machine backup disk is attached to a Mac mini, allowing my MacBook Pro to backup anytime via WiFi. The same thing can be accomplished with an Apple Time Capsule or an external hard disk attached to an Apple Airport Extreme.
A little known feature of Time Machine is that there are Time Machine “aware” applications. This is where you can do a Time Machine restore directly within the application. The applications which support this feature are Mail and Address Book. Let’s use Mail as an example.
1. While in the Mail application, launch Time Machine. You’ll see the familiar time line on the right hand side and the most current Mail inbox in the center of the screen.
2. Go back in time. You’ll see the state of your email as it was on that day. You can read or recover an email that you have since deleted.
This also works for Address Book. With Address Book open and in the foreground, launching Time Machine will allow you to go back in time to a previous date to view or recover an address book entry.
If you want to find out if an application is Time Machine “aware”, launch Time Machine while the application is running and in the foreground. If it isn’t Time Machine aware, you’ll see the Finder window appear when Time Machine launches. I’ve read that other applications are Time Machine aware, but my testing while running Lion has proven otherwise.