Everyone seems to have a different idea of what constitutes a *SPOILER* in terms of a book or o movie. There is a lot of nuance in what is enticing to watch a film, and what spoils the fun. Many people say, “I enjoyed that movie so much because I walked in totally blind to what it was!” On the flip side of things, the films of Wes Anderson, The Coen Brothers, Federico Fellini, Michael Haneke, and many more become more enjoyable after multiple viewings.
Who doesn’t come to Casablanca knowing about “Here’s looking at you, kid,” or “Play it, Sam,” or “Round up the usual suspects”? You likely saw the ending of King Kong in compilation films before you saw the whole movie, yet you probably still watch it with enjoyment. I saw Potemkin’s Odessa Steps sequence many times, on an 8mm reel I bought as a kid, before I saw the whole movie. I still enjoy Potemkin, possibly more than many who see it for the first time. Yet people complain about trailers that tell too much, and critics who give plot twists away. Accordingly, it’s been a convention of fan and Net writing that if you’re going to give away major story information, you alert readers with the word “spoiler.”
Surely people want to know something about a film’s story. Viewers clamored for the most basic information about Super 8. And evidently many moviegoers would feel less disgruntled about The Tree of Life if they had known in advance a little bit more about what they would encounter. It seems we want to know about the story’s basic situation, but not too much about how things develop. Say: bits from the first half-hour or so, up to the beginning of the Second Act (or what Kristin calls the Complicating Action). Beyond that, we want things kept quiet. Above all: Don’t tell the how things turn out in the end.
Also, see Jim Emerson on the subject (linked within the above article and here as well)