Besides, Veronica's dying to know (for some unknown reason) and I said I'd wait to see if anyone here bit.
So here goes
In 1996 my ISP, Worldnet, didn't offer free web space, so I thought I'd sign up for a Web-only account to get free webspace from a different ISP then called Concentric. I was reading Raymond Chandler at the time, and it was supposed to be a second account, so I used the username acedetective. Well they had a character limit, so it came out acedetect.
Then I found out my web-only account not only didn't include dial-up but didn't include the free web space either. So I decided to just switch ISPs and get the dial-up from Concentric. I had canceled the Web-only account, but it wouldn't let me use the username acedetect (probably because it was still in the database. So instead of picking something entirely different, I chose a variation, acedtect. That became my email, firstname.lastname@example.org.
On down the line, whenever I signed up for accounts, tmerritt was almost always taken, so I just started using acedtect.