Books and Black...?

Okay, I went to Hastings...I mean...it's not really a bookstore...but it has entertainment! And I was very surprised by the amount of black I saw on the shelves. I'm not dissing black, lol, but everyones books look the same!

Look:

and this one:

Does anyone else thing Twilight set off this trend? Do you guys think book covers are trends as well? Cause I definitely know that people judge books by their covers! But is there a mindset that "If this book looks like that book which is selling well, this one might too?"

Also: Anyone wanna way in on what agents mean when they want a 'bio' instead of 'query'?