Walmart expands online network to beat out Amazon

Online competitors should keep an eye out for Walmart, the biggest U.S. retailer out there. The superstore will rollout an online service that allows customers to ditch the lines when returning items. Walmart hopes the 'Mobile Express Return' option will help it stack up against Amazon, a major online-only player. Amazon recently acquired Whole Foods for $13.7 billion, expanding it's physical, non-hub presence to 400 locations. But, Walmart still reigns supreme with about 4,700 stores, and it estimated 90 percent of people in the U.S. live within 10 miles of one of its store locations.