See that? That blur up there is a detail from the new The Dark Knight Rises poster that a lot of people are saying is a clue indicating that a certain Man of Steel is going to be making an appearance. I'm not so sure myself, it just looks like a blur to me, but I suppose if you squint your eyes and tilt your head a bit, it looks a bit like the Superman symbol.
Even though Christopher Nolan is currently producing Zack "slow, slow, quick, quick, slow" Snyder's Superman film, I think this theory is probably complete baloney. Not because I doubt them using the promotional material in such a way – remember this is a campaign that kicked off with a hidden code in a sound file revealing a twitter account that gradually led to the piecing together of an image (more on that here) – but because it simply wouldn't work in the Batman world Nolan has created thus far.
Yes, I'm aware the two characters have co-existed in the comics for pretty much ever, and some times that has been amazing (you simply can't fault Frank Miller's The Dark Knight Returns). Mostly though, superhero crossovers and shared (multiple) universes just dilute the awesomeness of the characters. This is a problem the Marvel films are going to have to deal with, post-Avengers. Whenever Iron Man is in trouble, why doesn't he just give his patriotic/green/godly pals a call?
But this goes beyond plurality. Nolan has created a world in which a costumed vigilante fights organised crime using fear and wealth. Not an entirely realistic world, but one that has the right amount of internal logic for it to make sense and seem real. Sticking Supes in there would make it a world in which a costumed vigilante exists side-by-side with a flying super-powered alien. That's like making a sequel to Seven in which Detective Somerset find a portal to Narnia. It just isn't going to work. And I think – hope – that Nolan knows that.
I'm more intrigued by the poster's suggestion of an earthquake, perhaps drawing on the No Man's Land comics (plus Nolan loves nothing more than destroying buildings). Anyway, the first trailer is leaking/being removed all over the web as I type this, so maybe that'll hold some more clues. In other exciting teaser poster news, have you seen the one for The Thing prequel (confusingly called The Thing)? I'm a bit excited about that. "It's not human. Yet." is a great tagline. I just hope they stick to their guns and make it fit together with the opening of the 1982 film.