Ozz,
It's the Mark Of The Devil!
Kidding.
It's just a number they started to use not too long ago so that if we wished, we might add those numbers to our "MOC" bumperstickers, so others could look us up, without our having to write our entire nickname into a bumpersticker.
There may be more to it. But story that satisfies me.
Steve
P.S.
Oh, and, (someone correct me if I’m wrong,) there should be some way made to incorporate the numbers in with the “Members” listing, so we might search for a number we’ve seen and know who it was. I didn’t see the numbers on that list. And plugging my number in does nothing in a search, there.
S.