Mr. Mellow is a nickname I acquired in high school because I appeared to be unflappable (still true to some extent, but...). I started adding the "001" because it turns out that "Mistermellow" was already taken at several sites I've registered on, like eBay, Yahoo, Gmail, Dial-a-Skank, etc.
I've been thinking of asking Shawn to get rid of the "001," which is possible, but he's got enough on his hands and I don't want to bother him with it.