A dialect of typing that uses numbers and symbols to replace letters, and many misspellings. The name is a bastardization of "elite speak", as it was originally popularized to "look cool" and seperate one from word=noob
Examples of such replacements used in leetspeak are: 1's or |'s for l's and/or i's, 5's or z's for s's, @'s or 4's for a's, \/\/'s for w's, etc. People who use l33tspeak usually have their own form, using their own combinations of replacements and misspellings.
A popular form of l33tsp33k uses random capitalizations of letters that are not (or cannot be, in some cases) replaced.
Nowadays computer geeks, and those who spend much of their day in word=chat room
will use intermittent l33tsp33k to joke around with one another; true l33tsp33kers are rarely seen around the internet anymore.