"l337" in short refers to taking letters in words and relacing them with similar numbers and/or symbols, like typing "c4r" instead of car. 1337 comes out at "leet" which is short for "elite." (and there are many variations on even that, depending on how far you want to go: L33t, 133t, etc) Typing (and talking) like that is known as l337speak. In the early days of the internet it was actually used by the internet's elite hackers and the like to communicate.

Nowadays internet savvy people (well for the most part) know what l337 is, but never use it. Usually those who do use it end up being the butt end of jokes and ridicule because at least IMO, it's annoying, comes in huge chunks (imagine this post done completely like that), and almost always come from people who don't know jack about what they're talking about. As such these people are usually tagged as "n00bs" (noobs, newbs, newbies) as Ed put it, and even furthur making them targets for being made fun of

n00bs

And what's 1337?

i thought the P came from Pawn. like, i own your ass, you're my pawn.

you can make it more 1337 if you capitalized the 'w' and kill the 'e' like this:

pWnd!

It's from 'owned'. And 'p' is next to 'o'. And, apparently, typos and grammatical errors are 'teh funny'.

What does pwned mean? Well, I know what it means, but where did it come from?

Way to go, trivia fence-sitters. You missed it. We pwned them.

Listen up myspace pimps, I've got your new favourite whore. Teach that bitch whose shit. Give that slut the old Red Hot Daggers.

Negative for me