it means "Fuck This Shit". Used to express frustration and/or apathy.
I was waiting for the signal to change so I could cross the street in downtown Toronto and there was Charles. He was blitzed and he was wearing a shirt I've seen in America. It said on the top "Famous Oriental Saying" and had some slash marks below it. Turning the head sideways revealed that the "Oriental characters" made up the English words "fuck this shit". Charles repeated the "saying" on his racist T-shirt by saying "Yeah. Fuck this shit. FTS." The light turned green. We crossed the street, I turned east and he went west.