I can't imagine anybody here with a different username.
I thought somebody would already have MeechMunchie, and I was surprised that no-one did, so I took it. Also I always liked Meeches and the 'Extinct' poster. I suppose if it had been taken I would have been FlamingCarrot, which I use for most stuff. Looking far into the mists of the potential futures, I see RideTheWalrus or Infected. Though I probably would have come up with something on the spot.
I like MA's acronym because it sounds a bit like Murray (which oddly enough lead me to compose a new lyrics to the first verse of 'Cheer up Murray' while I was scanning the forums one day. I have sworn only to reveal these at a time of direst need).
Also, Used
makes me think of Acid. Probably the smiley. 'I got totally used last night' and so on.