Mine kind of signifies the fantasy that we're anonymous online. In other words, I don't like to divulge too much personal information, even though I realize that there's no real anonymity here.
Also, I don't usually post unless I have something meaningful (to me at least) to add.
Then there's my signature. I'm not really a scofflaw, but that's what I was called by one of our more staid members when I asked questions about a radar detector.
Edited to add: also, I do really know how to spell "stealth", but I like "Stelth" better for a screen name.