What is Long-Tailed Distribution?

Long-Tailed Distribution in statistics and business is the portion of the distribution having a large number of occurrences far from the “head” or central part of the distribution. The term is often used loosely, with no definition or arbitrary definition, but precise definitions are possible. Broadly speaking, for such population distributions, the majority of occurrences (more than half, and where the Pareto principle applies, 80%) are accounted for by the first 20% of items in the distribution. What is unusual about a long-tailed distribution is that the most frequently occurring 20% of items represent less than 50% of occurrences; or in other words, the least frequently occurring 80% of items are more important as a proportion of the total population.The long tail concept has found some ground for application, research, and experimentation. It is a term used in online business, mass media, micro-finance, user-driven innovation, and social network mechanisms (e.g. crowdsourcing, crowd casting, peer-to-peer), economic models, and marketing.