Wow. I have never looked back at when I joined or any of that business, but this thread prompted me. It seems I joined in Feb 2004 and my first question was a typical first visitor question about malaria pills.
Back in the 90's, when I first found the internet, I naively used my real name, which is Colette. Unfortunately, my name was interpreted as an invitation to tell people what I was wearing, what my cup size was and whether I wanted to 'cyber'.
I was working for this amazing autistic mathematician at the time and he couldn't really get his head around names, so he'd just use whatever worked best for him. In my case, I became 'Collywobbles'. My surname starts with a K, so I just used Collyk.
Weirdly, some people have assumed that I am a man who has named myself after a stomach disorder (colic), which I find quite funny.