why the '4' in w4lker?

I'm not trying to be 'l33t.

The problem is that John Walker is a relatively common name. For example, google John Walker and you won't find me. Every time I go to any site where I have to sign up, the permutations of john walker are already taken. I have found of late that I can, however, usually get w4lker, john_w4lker, john.w4lker, etc. etc. etc. Thus, I have been consistently getting that in the hopes that my friends will be able to find me... or at least recognize the pattern. :-/

(thanks to ShadowBoxer for this image of olde)