Most people here seem to be "against" reading spoilers for TDK...
I'm kinda partial to reading spoilers, cause I dont see a point in avoiding them, really...
TDK is a Batman movie, so right from the start, I pretty much know everything there is to know about the movie. I know the Joker is in it. I already know who the Joker is (from the comics, tv, etc.), what he does, how he will act... I know Batman will fight the Joker... I know Batman will live... I know Harvey turns into Two-Face... I know pretty much HOW Harvey turns into Two-Face... I know Alfred, Gordon won't die... I know Gordon will become Comissioner eventually... I pretty much know Batman's character and can take an educated guess as to the internal battle he will face in the film... I mean, for the most part, because this movie is based on a comic book character with decades of established history, I pretty much can take educated guesses as to everything that will happen in TDK
So in a way, because I know a lot about Batman, TDK is already spoiled.
A movie like Cloverfield is a movie I would avoid spoilers. That movie was a mystery, it was marketed as a mystery, and I didn't know anything about it. But Batman...is...well...Batman. I know what I am getting before I even get it. So... I may be tempted to read spoilers before TDK's release. That doesn't mean I won't enjoy the film and go see it five, six times...
Greg