I'm probably late to weigh in on book trailers, but Jason Boog posted something on eBookNewser that made me think about them again. Recounting an interview he had with WNYC he said:

My hope is that someday the extra interviews and other kooky things that authors are creating to support their books can actually be included inside the book, like DVD extras inside of a digital book.

The comparison to DVD extras is apt, because when was the last time you watched the extra scenes or listened to the director's commentary on a DVD? And why the rush to add this junk to books?

I don't think it's old fashioned to say that I want a book to be a certain thing, a long-form body of text that tells some kind of story. Whether that's on paper or pixels makes no difference, the fundamental piece of art is the same.  I've heard people criticize the notion that e-books should be simple digital reproductions of print, that instead we ought to take advantage of the technical possibilities to enhance the medium. But all those bells and whistles have the same relationship to a book that the kiss cam and the mascot shooting hot dogs out of a hydraulic bazooka at a major league stadium have to a baseball game. They might be a good way to market the game to people who might not otherwise be interested, but to the true fan they're annoying, unnecessary distractions.