Amazon’s book-selling rankings are becoming increasingly influential in promoting a book. “Amazon is an early indicator of consumer enthusiasm. It’s a place where you look to for early signals as to a book’s potential in the marketplace.’ Authors indeed are paying increasing heed to Amazon’s unique and influential role in publicizing and selling books. While the company doesn’t break out its books sales, it sold $1.7 billion worth of books, music, videos and DVDs for the first half of the year.”