Wal-Mart (NYSE: WMT) is the best example of a traditional retailer trying to revamp and revitalize its business via e-commerce. One major aspect of those efforts is delivery, getting goods to customers as quickly and cheaply as possible. Though Amazon.com (NASDAQ: AMZN) boasts an expansive network of fulfillment centers that put it within a 20-mile reach of 40% of the U.S.