Talk:Mystery Vault/@comment-72.215.14.78-20100413204338

It's the number that Facebook recognizes you as...

If you don't know your UID, go to your profile. RIGHT CLICK on your Profile Picture and select.... OPEN IN NEW WINDOW.

Look on the URL line of the new window... you will see something like...

http://www.facebook.com/album.php?profile=1&id=##############

The numbers after &id= is your UID