Term used in the fighting game community, mostly among old school SF and KOF players.
QCF stood for Quarter Cirlce Forward, and was a term used to denote joystick input that would cause your character to perform special moves.
To throw Ryu's fireball, motion the joystick QCF and press a punch button.
An extension to the exclamation point exxageration craze, in tune with leet speak.
OMG WTF HAX!!11!one1shift+one11eleventypie!