Also, if I buy a book from Amazon instead of the local bookstore, then I can spend the money I save (from Amazon's discount off the list price) on other local businesses, such as restaurants. And the UPS driver who delivers the book to my door presumably lives in the local area, so he's going to be spending much of his salary in the local economy as well. His local job might not exist at all if not for the extra demand that Amazon and other non-local companies make on delivery services. I'm skeptical whether the analysis that was cited accounts for all these factors.
