Warners have come up with a cracking wheeze, as we so often say here in blighty.
A site has been set up that, originally at least, shows a defaced version of the Harvey Dent campaign picture. Underneath is a box for surfers to enter their e-mail addresses - and their reward? They receive an e-mail from 'tragicpast', complete with a pair of co-ordinates that will reveal one more pixel of a hidden picture. The more surfers input their addresses, the more picture is revealed - and the inference is, quite clearly, that we're going to see The Joker taking shape back there. I would hope that after 50% or so has been chipped away they'll just pull back the curtain - who's going to sign up just to de-fuzz Heath Ledger's face?
Ah, Warners. You know how keen people are to see The Joker. So keen they'll give you their e-mail addresses even though there's no indication at all what you'll be doing with them.
[EDIT: Yahoo and Hotmail accounts don't appear to be working with the site. Anybody prepared to try the various temporary e-mail sites to see if we can blast through this thing in a hurry?]