Answer:
The Shadow Copy feature is an amazing new recovery feature in Vista that is available in the Business, Ultimate and Enterprise editions. Shadow Copy is turned on by default and is a very useful tool when recovering a previous version of a file or folder.

Example you are editing a file and you accidentally make an error and save the file. With Shadow Copy, all you need to do it right click the file and select "Restore previous versions" from the resulting menu. Since Shadow Copy makes "points in time" snap shots of your files and folders you can easily restore any of the available versions of your file.