Alright, so here's my theory, which you can feel free to critique or ignore, but I figure it can't hurt to put my thoughts down for people to see.
Let's start with the eponymous trailer, which is the root of this whole situation. Now, there are various clues that scattered throughout it that have linked us across the Internet to more of the mystery.
www.slusho.jp is one such site, which is referenced by a t-shirt worn by a character in the trailer. Another site is the
www.abz3293.com site which mysteriously asks for information regarding the driver of a car in the trailer, who's license plate number is seen only briefly. The release date of the movie itself has been traced to a Bible verse, Romans 1:18, which reads: God’s Wrath on Unrighteousness,For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who suppress the truth in unrighteousness. This has been linked to the site
www.anti-christ.com, which referenced this passage and other apocalyptic verses as well.
As to the Ethan Haas saga, we know this. EHWR seems linked to the game studio Mind Storm Labs, which is developing a tabletop RPG known as Alpha-Omega, which apparently deals with after the apocalypse, when angels, demons, and humans fight it out for survival. So, this game seems to have the same quasi-religious overtones as Cloverfield, but apparently nothing else. However, after looking at their website, which is almost totally barren of any real information, I doubt their legitimacy. I think that MS Labs and their game are either real and tie-in to the movie or they are totally fake but may have relevance to the plot of the movie or the ARG.
The Slusho site seems unrelated except for the t-shirt. However, the domain name was registered only a week before the premiere of the trailer, but the website purports that the drink has been around for some time. The History link as well seems a little suspicious, as the story sounds like it could be related to the monster of Cloverfield or other plot points, despite the childish tone.
ABZ 3239 seems to be a totally legit viral site for the movie. After all, there's too much of a coincidence involved for it to be anything but a front for the movie.
As for the Anti-Christ site, this further reinforces the religious overtones or plot points of the movie, which seems linked to the movie based on the 1-18 1:18 link and the other related verses.
To draw attention back to the trailer, there is a line in the trailer, as they are coming into the street, that has many debating. Some say that when someone asks "What is it? Is it coming this way?" a man shouts in reply, "It's a light, it's huge!" Which would seem to make sense, given the massive fireball seen in the trailer. However, others hear, "It's alive, it's huge!" which also ties into the supposed giant-monster theme of the movie. The last, and most intriguing phrase is, "It's a lion, it's huge!" This is interesting because apparently, in the Book of Revelations, the Beast that shows up during the Apocalypse has the head of a lion. Very curious.
Now, while we wait to see if JJ was just trying to mislead us with his comment on EHWR, we'll work with only the other evidence at hand. Maybe we can come up with something that makes a lick of sense, or maybe I'm just crazy and my shift at work today could've been spent more productively than scribbling this on the back of an old receipt.