I ran across a blog post this morning that I thought was pretty interesting. Note the section under middle grade regarding "marketing platform or media hook." Those are terms usually reserved for adult nonfiction. Go figure.
http://kathytemean.wordpress.com/2010/06/15/state-of-the-childrens-book-publishing-industry/
http://kathytemean.wordpress.com/2010/06/15/state-of-the-childrens-book-publishing-industry/