Warning! Contains Spoilers!

Rosebud was the name of his sled.
Darth Vader is Luke's father.
Norman's mother is really dead.
Dil is really...a man!
Anna Karenina throws herself in front of a train.
Hamlet dies, Romeo and Juliet die.
The shark dies.
Rhett leaves Scarlett. The murder was committed by everyone on the train.
James Bond wins. Indiana Jones wins. Apollo Creed wins. Rocky wins. Bullwinkle wins. The tortoise wins.
Roger Aykroyd was killed by the narrator. Dorothy wakes up and discovers it was all a dream. Marcel remembers the past and decides to write a very long book about it. The bride's name is Beatrix Kiddo.
Peter runs away from Mr. McGregor and goes home wet and tired while the other rabbits have a good time. Everyone lives happily ever after. The world ends with a whimper, not a bang.

Have I made my point? From gossip sites to academic e-mail lists, it appears that there are an awful lot of people who can't enter a discussion about film without first acknowledging the official Internet Taboo against Spoilers. Can't we drop this silly pretense?
First of all, it rests on the notion that the only reason to see "Psycho" or read "Anna Karenina" is to find out how the story ends. Once we learn that, we can cast the work aside and move on to the next one.
And who exactly do the Spoiler Police believe they're protecting? If your imaginary reader is going to be irritated/devastated by narrative details, whether it's in a critical discussion or a report on a preview screening on "Ain't-it-Cool-News", then why are they reading it?
Obviously, there are times when common sense should prevail. Anyone writing a review of the hypothetical "Mystery of the Old Dark Mansion" probably knows to respect the convention of revealing what is obviously intended as a surprise. (I once got an editor angry with me, after having already warning me against mentioning the ending of a new film, because she claimed that I had inadvertently provided information that allowed her to figure out its climactic plot twist..)
In the long run, the Spoiler Police are just another symptom of the increasing Superficialization of all critical discourse. The writer who cautions that his message "contains spoilers" is really just using it as a come-on, a promise of inside knowledge in a disposable culture. "Step right up, folks. Hey you, over there looking at that copy of "Ulysses".. The guy makes it home while his wife is in bed having smutty dreams. That's old news, forget it. Now you want something new, like the scoop on "X-Men 3"? Come on over. Let me tell you about it... "