There are lists of these abbreviations and their meanings, e.g. here .
Here’s my explanation of popularised internet-based distortions of English words (similar to SMS language).
“l337” = “leet” = elite, meaning “cool”.
“Leet-speak” is computer-nerd language, where numbers are substituted for letters, l1k3 7h15.
17’5 qu173 345y 70 r34d 0nc3 y0u g37 u53d 70 17.
“n00b” = newbie = a new person who doesn’t know much yet.
Sometimes used in a derogatory fashion by people who feel that living in front of a computer makes them better than others! :P
“w00t” = “cool”, “excellent”, “yeah baby”, etc.
It comes from “won the root” or “we own the root”, which is a hacker’s way of saying they’ve got hold of a computer’s master password (the root). Someone more recently suggested it stands for “We Own the Other Team”.
“Pwn” (pronounced pone or poon) is a computer-gamer word that comes from writing “own” but accidentally hitting the ‘p’ instead of the ‘o’. “Owning” someone means beating them.
Like pwn, “teh” is an alteration of “the”. But you can use it differently, like “this is teh cool!”
Related is
“Uber” = über (pronounced oober) = German for “over”.
Has been adopted in English by nerds and clubbers to mean “ultra”, “super”, “maximum”, etc. I believe it appeared first in rave culture.