This one's fairly hard to categorize, but based on the style of writing, alone, I can firmly place it in Horror. 
 I have to say that I'm really enjoying all these recent epistolary novels. I always thought the old styles even from classics like Dracula were kinda overblown, but these fit me just fine. Sure, they're transcripts from skype conversations and emails and message boards, but who cares? It lets us see all the kooky craziness of a wide, wide swath of weird humanity, and that's rather the point. 
 The Three (or four) that the novel is ostensibly supposed to be about are rather beside the point. They're merely a fraction of the creepy that this novel has to offer. 
 No. The real monsters, the real aliens, the real possessions, and the real androids are right here among us normals. Hell, there were several references to Left Behind, enough to really point out that this was either a tribute to the whole Rapture scenario or it was one of the most deadpan satires of it. I tend to believe the latter. 
 *shiver* The United Theocratical States of America. Yikes. 
 This is real horror. 
 In the end, it doesn't even matter what the titular characters were, although I'll think about it for a while and probably pick up the sequel because the question is still interesting. The best part of the novel was in looking at the mirror of our societies and all of our deep dark ignorance and our crazy. 
 It was great fun! It was kinda relaxing and let me get my hate on for all the idiots of the world. Isn't that the point? 
 All of the characters were pretty damn detailed and immersed us in the world. The devil is always in the details for the horror novel, after all, and this succeeds quite well. I'm very glad to have read this, even if it's not mind-shattering, truly horror inducing, or terribly original. It is, however, solid and fascinating and modern and tongue-in-cheek, so I'm going to sing it's praises. :) It IS well written. :)