Just because I'm too lazy to retype it, I'll copy and paste from
an old post.

It all started way back when I first got Net access in November of 1996. I opened an account with AOL (yes, you can all either laugh or radiate sympathy in my general direction, depending on your disposition), and needed a username. I knew I wanted something more unique than just my name or initials, and didn't have lots of random numbers after it, but all of my childhood nicknames were... well... decidedly less-than-flattering. (The only two that weren't horrible were "The Brain", which I feared would set up an incorrect first impression, and "The Walking Computer", which would have been amusing, but was too long.)
Finally I somehow hit upon "Jelsie". J from my middle name Julia, and "Elsie" from my first name, as well as a friend whose middle name was Elizabeth and sometimes liked to go by that nickname. Well, "Jelsie" was taken. And so was "Jelcie" and "Jaycie" and so on, until I finally hit upon "Jeysie". It wasn't taken, it sounded kinda neat, and it meant absolutely nothing. Perfect! And since I'm a creature of habit (not to mention desiring to keep a consistent online "persona") I've just used the nick for every online thing I've done that needed a username... and it's never been taken so far.
I've been using the same "post signing off" method for all this time now as well, for similarly boring yet quirky reasons.
Peace & Luv, Liz