This slang term was coined by those who believe in the US government involvement(namely the CIA) in the creation of Al Quieda during Afghanistan's fight against the invading soviets , thus using this "front group" to mask the US involvment in the events 9/11 to achieve various goals(Middle-east wars, invasion of American rights under the guise of a "global war on terror", etc). I believe this was first coined by the widely known founders of 9/11 truth movement such as Alex Jones and John Stadtmiller of Austin,TX.