Printed, stored, and shipped to you. While I'm not sure exactly what shipping costs across the industry (not just Amazon sales, where you can see exactly what

Printed, stored, and shipped to you. While I'm not sure exactly what shipping costs across the industry (not just Amazon sales, where you can see exactly what you'll pay for shipping) for getting physical books into people's hands, shipping is only getting cheaper for e-books (some more recent Kindles don't support 3G whispernet, so there's an infrastructure middleman cut out, and the cost for shipping approaches zero as the cost for bandwidth approaches zero), there by widening the gap between physical and e-books.