pwned meaning Owned being bested without any chance of retaliation.
wtfpwned meaning the person does not understand how they where bested without having a chance for retaliation.
They Wtfpwned him!
(In a split second, Fred busts the door open without the consent of Jim!)
(Jim's quick reflexes call for a beautiful headshot on Fred's gay ass character)
Jim: WTF PWNED! you damn noob! suck mah balls!