Think for a moment about the logical progression of retail: A century ago, we got most of our goods from local stores owned by people we called our neighbors.

But then, starting about 50 years ago, nationwide retailers -- led by Wal-Mart (NYSE:WMT)-- started to capitalize on the efficiency of scale and offer goods for far lower than mom-and-pops could. Indeed, shareholders in Wal-Mart have realized astounding returns since the company's IPO. And the company is still one of America's largest employers, with 2.2 million finding full-time employment at their local Wal-Mart.

But every giant can be disrupted, and that's what (NASDAQ:AMZN) has been doing to Wal-Mart, little by little, for over a decade. In addition to offering a more convenient way to purchase goods, Amazon has expanded well beyond the realm of retail to be a dominant player in areas like cloud computing, streaming movies, and e-readers/tablets.

But in just three months' time, a quarter of Amazon's market cap -- or roughly $45 billion -- has disappeared. Bears have legitimate concerns about the company moving forward. The Motley Fool's Brian Stoffel introduces investors to these broad concerns and what he thinks about them. Watch to see whether Brian thinks Amazon can continue to outpace traditional foes like Wal-Mart and if the stock is still worth holding on to.

Brian Stoffel owns shares of The Motley Fool recommends and owns shares of 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.