Tim Wu in Slate:
Chris Anderson’s The Long Tail does something that only the best books do—uncovers a phenomenon that’s undeniably going on and makes clear sense of it. Anderson, the Wired editor-in-chief who first wrote about the Long Tail concept in 2004, had two moments of genius: He visualized the demand for certain products as a “power curve,” and he came up with a catchy phrase to go with his observation. Like most good ideas, the Long Tail attaches to your mind and gets stuck there. Everything you take in—cult blogs, alternative music, festival films—starts looking like the Long Tail in action. But that’s also the problem. The Long Tail theory is so catchy it can overgrow its useful boundaries. Unfortunately, Anderson’s book exacerbates this problem. When you put it down, there’s one question you won’t be able to answer: When, exactly, doesn’t the Long Tail matter?
This image accurately describes the demand for cultural products. In most entertainment industries (films, music, books, etc.) a few hits make most of the money, and demand drops off quickly thereafter. Demand, however, doesn’t drop to zero. The products in the Long Tail are less popular in a mass sense, but still popular in a niche sense. What that means is that some businesses, like Amazon and Google, can make money not just on big hits, but by eating the Long Tail. They can live like a blue whale, growing fat by eating millions of tiny shrimp.
This insight goes only so far, but like many business books, The Long Tail commits the sin of overreaching.