Walmart's Dot-Com Division Plays Catch-Up with Amazon

America's biggest retailer is going online, while the country's leader in e-commerce is constructing new buildings. Walmart, known for big box stores full of discounted everything, from tires to organic milk to tires, is increasing its presence on line. In Amazon it has finally found a competitor it's worried about. Claire Cain Miller, who covers technology from San Francisco for the New York Times, has more on the competition between Walmart and Amazon to sell you just about everything.