I guess I should start, though I think my username has a pretty juvenile origin. Back in my early days on the internet, I would often sign emails with a giant version of the winking emoticon instead of my name. It looked like this:
A friend of mine referred to it as "The Face" and I started using it as a name online for lack of anything better. DaFace is a little shorter and has a little better ring to it, so I've stuck with it for nearly 10 years now!