Okay, I shall explain the few things I know.
stands for Big Guy Mask
(or Big Girl Mask in a few cases!), and it started back in the hayday of this forum and XWA, back in the days of people like GUNNER
, Lt Guilo
, et all the other forum legends that you know of.
It was "awarded" for fun to people after they reached 600 posts, and was not taken too terribly seriously, except possibly as a sign that someone had spent far too much time here
However, this is the first I've heard of it being a private thing that no one else was able to use; must be a new rule.