Leet speak

Originating in the early 1980's, leet speak was first used by hackers as a way to prevent their websites/newsgroups from being found by simple keyword searches. Leet speak grew and became popular in online games such as Doom in the early 1990's as a way of suggesting that you were a hacker (h4x0r), and therefore to be feared. Leet, or 1337, is a short form of "elite," commonly used by video gamers to suggest that they are skilled.