Well, I think they're going a bit too far there with the whole idea of rating books, but seriously, have you read a teen book recently. They're pretty much wrecked by the drop of an F-bomb on every second sentence, on top of that, someones doing someone else on every second page. Now I'm not saying that's a bad thing, but when reading it, I just can't take it seriously, considering the fact that half of these books always seem to feature some kind of misfit, unlikeable bunch of teens who try to come off as somehow mature throughall the afforementioned content, it just becomes stupid. It's the equivalent of a 5 year old attempting to trash-talk with a straight face, or a game being over the top in terms of the characters all being whiny, brooding unlikeable dipshits, all who do it with a straight face (Here's looking at you prototype).
