it's like dumb computer language or something... it's like when people say pwned for owned... it used to be on accident, but then people started to do it on purpose. kinda lame i think.
I've been reading up on L33T for a few weeks now, that's mainly where "teh" and rOxOrz and stuff came from...hAxorz or Hackers used to use weird messed up characters in they're writing on chats and stuff to show that they were ELITE, spelled it 3L173, then got shortened to L33T or L337.....anyway, yeah, teh originally came from there as weird computer talk