I just got an email from the Senior Publicist at Entertainment Weekly -- wow, how important I must be! -- about an online article they have with more info on the Cloverfield trailer (I wrote about this movie early enough after the trailer was released that BA comes up pretty high on Google if you search on "Cloverfield"). The article is no big deal, with almost no new info; all it really does is confirm it's a monster movie, but doesn't say how they know.
The poster shown above is spreading through the Intertubes right now (like on Slashfilm), since it was released at ComicCon today (together with a Star trek 11 poster which isn't worth showing here; it's just the words "Star Trek: Stardate 12.25.08").
Anyway, the EW article refers people to the Cloverfield site for more info, but there is only a Flash animation there with no info. It may be some sort of Easter Egg hunt, but I have no patience for such things. If anybody figures out more, feel free to comment!