Reading mangas can lead to new and interesting discoveries:
Initially, the word l33t was used as an adjective, to primarily describe the behavior or accomplishments of others in the community. In that usage Leet generally carries the same meaning when referring to either the game prowess or, in original usage, hacking expertise of another person. From adjective form its use then expanded to include use as an expletive or interjection in reaction to a demonstration of the former qualities. With the mass proliferation of Internet use in the 1990s into the 21st century, Leet has since become a part of Internet culture and slang. Leet may also be considered a substitution cipher, albeit with much variation from user to user.
(Excerpted from the Wikipedia page for Leet.)
You know what’s really l33t? Megatokyo no. 9:
This was one of the strips that got me hooked on the series way back when. You should get hooked, too. 😉