When I was first on the forums which later became the Dimensions forums I suddenly had to come up with a user name. I was trying to think of something descriptive of my interest in the FA/fat-accepting/feedist community (this was pretty much THE place on the web for all things fat-love related back then, so it pulled in all kinds). But I felt that I was a bit of FA and a bit of liking being fat and a bit of a feeder and a bit of a feedist -- or to sound a bit more pretentious about it all I was a tad of this and a tad of that, and voila I had my user name.
(I did change to Edx for a while (Ed is my middle name, x was because I'd tried Ed, Ed2, and Ed3 but back then names were not registered, you chose a name every time you logged in, and those others kept getting grabbed, so being a math nerd I made the obvious sequence jump of '0, 1, 2, ...., x' and went to Edx. When other sites on the web began to cover portions of this community I was using Edx here and kept that name on other sites. Then I switched back to Tad here because nobody understood 'Edx' without an explanation. Then later I had the idea to change my name on those other sites to Edxl (Ed, sized XL), which is outdated now but Ed2xl seemed even more confusing ... I'm glad I'd just switched back to Tad here)