Wal-Mart (NYSE:WMT) may generate more than seven times the sales of Amazon.com (NASDAQ:AMZN), 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.

Longtime Fool contributor Rick Munarriz has no position in any stocks mentioned. The Motley Fool recommends Amazon.com. The Motley Fool owns shares of Amazon.com. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.