The Dark Knight has been promoted more heavily through viral sites on the web than any movie since The Matrix. We've been treated to promotional images and messages through such sites as IbelieveInHarveyDent.com, IbelieveinHarveyDentToo.com, WhySoSerious.com and RorysDeathKiss.com.
Now we can add one more site to the list. The user lucafon left a message on BlogCritics that there has been another site discovered. harveydent.piczo.com, which is a part of the social networking site, Piczo, has what may be a picture of the poster for the movie.
Beneath the poster there are a set of hidden letters, containing maniacal laughter from the Joker. If you extract the "Ha"s from the text, there's another hidden message. "Look for my smile December."