Or the origin of the word sh*t? Back in the day, when manure (used for fertilizer) was transported across bodies of water in the hulls of ships, unknowingly allowing it to take on water and create methane gas. Some poor guy with a kerosene lantern would go down, and blow the ship up. After losing numerous ships and crew, they finally figured out the problem and started transportating it all in wooden crates, stamped with S.H.I.T. Meaning "Ship High In Transit". Officially answering the question of why a 'shitload' refers to pooh..