It blew my mind when a year or so ago, a guy in the movie industry stated that studios WANT trailers that basically give away the plot. Apparently, for every person who is pissed off and complains about trailers that show everything but the very ending, there are a lot more moviegoers who want to know everything but the ending before they head into the theater.
And now there is this Wired story that explains how some people enjoy spoiled stories more.

Now, one of the reasons that I don't think this study necessarily correlates to film is that I feel that reading is far more involved and even when reading a short story, the journey is the thing. I believe that in literature, a good 2/3's of a story isn't ruined by a bad ending as much as film. One reason might be, ironically, the shock of a bad ending in a film. When reading, you can kind of find a spot where the film goes downhill. Many films don't go downfill, they plateau and there's more of a "What the hell happened?" feeling.

Anyway, I still hate spoilers and like comedies when I know as few of the jokes as possible. The one thing that I do think the new No Spoiler craze has hurt is film criticism because so many critics try to write their readings of the film without giving anything away, which is counterintuitive. Film criticism can't really truly begin until the film is presented (or spoiled) and then the critic investigates or breaks down what exactly it all meant. But that's a horse that I've beaten to death so I'll just stop before I rant on about Reviews vs. Criticism.