Usually referring to an online video that is set up. An alternative of fake or staged. First used by mistake on wtfpeople.com by nuII. It was then reused by another member VipeNero to humiliate him. Since then it has become a word in itself.
From surfing slang: to be struck in the back of the head by someone else's surf board. Applied generally to any instance in which the actions of another are underhanded and destructive.