‘Dark Knight’ secrets slowly come to light

The “slow reveal” viral campaign for Batman prequel-sequel The Dark Knight continues to creep along, with this week’s highlight being the first full photo of Heath Ledger as the Joker. The image was unveiled with the same deliberate pace that has kept die-hard fans salivating for months. (Perhaps too deliberate, as it was actually leaked early, according to Movie Marketing Madness.) While most of the promotion in the campaign has been slim on content, fans were inundated recently with four full pages of exhaustive copy from an