Amazon is the world's largest e-commerce company, while Walmart is the world's largest retailer. Both companies are merging their online and offline channels to improve customer experience. Amazon is focusing on same-day delivery through a crowd-sourced approach, allowing customers to receive products quickly and conveniently. On the other hand, Walmart is offering discounts but faces challenges in making up for lost time and revenue. The article highlights Amazon's success in overcoming supply chain challenges and its ability to adapt to changing market conditions, making it more likely to overtake Walmart as the world's largest retailer.