>>He was only joking - he linked to Bing.
>
>Yes, surely I guess. :) But, I am still wondering about the specifications of that service. Whatever I found is very generic. Even on Microsoft site, there isn't too much information.

Looks like it is used by any program that needs to make a backup of files even when they are in use including by Windows Restore Points and Windows Backup - http://en.wikipedia.org/wiki/Shadow_Copy