Even so, don’t you fuckin’ love this board? 
It means “own” and the second paragraph of that Wikipedia definition came first. I saw them being used interchangeably as early as…1995? 1996 at the very latest. Crossover between internet security hobbyists and FPS players saw its migration from IRC channels into gaming servers shortly thereafter. But it was originally just what someone would say (type) when they had root (or claimed to have root) on a box not their own. Root = woot, which is why you have woot as a happy exclamation getting popular at about the same time. Woot died out about five minutes later for obvious reasons, but “pwone” survives and still gets used even if only ironically.
No, you’re right, I take that back. It was adopted ironically, if anything, not as a correct spelling in earnest.
I think any arguments that “pwn” originated from any source other than common mispellings just doesn’t hold water in the context of the usage. As others have pointed out, it is often used in conjunction with other words like “teh” “kewl” “lawl” “!!!1” etc. Besides the fact that if it stood for “powerfully owned” “pown” would make more sense, common phrases will more often have an accronym than some sort of contraction.
Woot is hardly dead. I see it used all the time.
EDIT: One example: woot.com
Woot is an excellent exclamation to express pleasure, like woo or woohoo. Woot.com is an awesome website. w00t is just silly.
Revision: Woot died out about five minutes later [amongst its originators and early adopters but persisted amongst script kiddies and gamers for years to come, causing pain and unmitigated flinches of nostalgic horror for the former group] for obvious reasons, but “pwone” survives and still gets used even if only ironically.
Oh, how I wish. It seems to have made a resurgence among geeky girls.
Why are you spelling it like that? 
Anyway, I and many others still use it non-ironically today. I really don’t think it became a part of the mainstream gaming lexicon until the early 2000s–or at least, that’s when I first noticed it, and I was a Frag God in Quake 1.
You want a real kicker? Ask where ‘re’ came from.
I been hangin around IRC since 1993, which is back in the early-ass days of that. I don’t remember when I first saw pwn. I remember woot, then woop, then qoop, and all of those dying out by like… 1995.
But good old ‘re’ … still around.
Of course, to be truly l33t is to use these terms entirely without irony and only in the situations they were coined in, because anyone using them for plain old colloquial shits 'n giggles fun is obviously some out-of-it wanna-be who is mocking and disrespecting the authentic culture.
Aha, I am not alone. I also read in as though it were Welsh, and think of it that way. It’s lucky that I never have to say that word out loud in the real world. 