Although no one knows exactly when Quickscoping was created ,one can assume that it started with the birth of Call of Duty. Quickscoping has and always will be a controversial topic, a large part of the Call of Duty community believes it takes skill and precision: where as many also consider it to be a cheap game mechanic that is far too easy.
Love it or hate it, Quickscoping is a huge part of the Call of Duty culture.
Moaning music (lol) :
MW2 Menu Trap Remix