I'm a fan of blogs. I have about twenty blogs that I read every day. I recently found a new one that hooked me instantly, and I was on it for about two hours reading back posts.
It's called Jacket Whys and follows the trends in YA and Children's book covers. If you follow the publishing industry, you're going to love this site.
Go check it out, but don't say that I didn't warn you. Be prepared to spend a lot of time looking at all the covers for books from around the world!