Studios and stars alike have been urging fans to keep plot points secret so other viewers get the maximum impact, but this is nothing new. Fear of spoilers is good for business - it always has been. Here's why:
On May 1 1999, bookshops around the world began selling an item that today would be considered commercial hara-kiri.
It was the complete illustrated screenplay of Star Wars: Episode I - The Phantom Menace, written by George Lucas and accompanied by hand-drawn storyboard panels showing scenes from the forthcoming film.
That's right: forthcoming. Because The Phantom Menace itself would not be released in cinemas for another two and a half weeks, by which point any interested party could have familiarised themselves with the entire plot of one of the most hotly anticipated films ever made.
Did it matter? Not on