It sounds like gibberish, but I've used this as my internet name since 2005!
It comes from names which utilise all 3 Missingno forms in Pokemon R/B/Y, the letters are X, Y and Z. However, I only have the X and Y in my name!
I started a new game on my Pokemon Red but couldn't find a suitable name using all 3 characters. In the end I scrapped the Z and thought again. Eventually I came up with Ikwaylx, and it stuck with me, so I kept it ever since!
Just think, I've had this name since I was 11 or so..