These observations and their strategic implications have been explained by Chris
Anderson in his bestseller The Long Tail. 70 The long-tail phenomenon is that 80 percent
of offerings in a category are not big hits (see Exhibit 7.12 ). It turns out that 80 percent of
sales in a given product category (such as movies, books, and songs) come from “blockbusters”
in the “short head” of the distribution curve, which represents only 20 percent of
the offerings in a category. This phenomenon is captured by the Pareto principle , also
known as the 80-20 rule, which says that roughly 80 percent of effects come from 20 percent
of the causes.