Wal-Mart (WMT +0.99%) may generate more than seven times the sales of Amazon.com (AMZN 0.87%), but there's a good reason that the world's largest retailer is beefing up its online presence.
In this video, longtime Fool contributor Rick Munarriz explains why Wal-Mart is getting its actual stores and regional warehouses into the act of online fulfillment in a bold attempt to take on Amazon before it starts delivering groceries -- and more -- to your door.
