For an independent bookstore, few threats are bigger than Amazon. With its e-book store and brutally competitive print book prices, it can be hard for a family-run business to compete. Well, it's only going to get tougher now that Amazon is expanding its footprint of physical stores. The company has confirmed it'll be setting up shop in Chicago and Portland -- these locations will be joining Seattle, which opened in November, New York and San Diego. The details of each store is under wraps, but it's safe to assume they'll be packed with Kindles and Kindle Fire tablets.