The document discusses the concept of "the long tail" and how it has developed with the emergence of Web 2.0. The long tail theory proposes that niche products which individually sell few units but collectively make up a large portion of total sales. With Web 2.0, as the internet became faster and more sophisticated, it allowed online retailers like Amazon to cater to niche audiences by offering a vast catalog of products beyond what physical stores could hold. This helped popularize the long tail theory and benefited more sellers by opening up new markets.