It's a dumb story. Really, it is. But everyone wants to know. So here's the official version.
When we were in high school (N.B.: this sets the story in the late 1980s), my beloved friend Lisa Cozza decided one day that the two of us ought to have really obnoxious pet names for each other, for the express purpose of annoying her parents. So, when I would walk in the back door of her house, I would call out adoringly, "BUTTERCUP?", and she would shriek down the stairs, "MUFFIN!"
The novelty soon wore off this, but the names stuck.
When I got to college, our campus radio station, WBRS, had a call-in talk show known as "Quality Time," where all the regular callers used nicknames on the air. I've never had much of a nickname really (you can't do a whole lot with "Erica," although my dad used to and still occasionally does call me "peanut"). So, thinking this was really cool, I started calling in as "Muffin."
Our junior year of college, my equally beloved friend Cos bestowed this World account on me for my 19th birthday (N.B.: this means I have in fact been online since 1991). So what did I pick for my username? Uh-huh.
I swear, if I had known I would still be explaining it ten years later, I might have thought better of it....
NEW -- Muffin Links! Excluding all the porn sites.
Q: So... what kind of muffin are you?
(heh heh, heh heh, heh)
A: Chocolate chip.
Q: But what's up with "std.com"?
(heh heh, heh heh, heh)
A: In fact, it stands for "Software Tool & Die," the name of
the company in Brookline, Massachusetts, that owns the machine (and hence
the Internet service) on which I have this account. "The World" is the
name of the machine, inside the "std" domain. (I went looking for a
layperson-friendly explanation of hierarchical naming conventions on the
Internet, but haven't found much; suggestions are welcomed. Meanwhile,
suffice it to say that this domain name long predates the rise of
"dot-com" in the public consciousness. >:-) The company seems to be
deprecating "world.std.com" in favor of "theworld.com" nowadays, anyway.