Pwnage is used to decribe superiority over someone or something, usually used in internet gaming.
Pwnage is from the root "word" pwn, originated when the map designer of Warcraft was spectating a match. The player lost to a computer character, so the map designer tried to type, "You got owned," but mistyped it, saying instead, "You got pwned." In other words, the word originated from a complete and total typo.
(After killing something in games without trying) PWNAGE
(After getting killed) That was pwnage.