An Amazon employee described the Long Tail as follows: "We sold more books today that didn't sell at all yesterday than we sold today of all the books that did sell yesterday."[4] In the same sense, the user-edited Internet encyclopedia Wikipedia has many low-popularity articles that, collectively, create a higher quantity of demand than a limited number of mainstream articles found in a conventional encyclopedia such as the Encyclopædia Britannica.[5]

The term is derived from the XY graph that is created when charting popularity to inventory. For example, in the graph shown above the total inventory of Wikipedia articles is along the bottom line, while the popularity rating (web page hit statistics) is along the vertical axis. So, for example, the Wikipedia homepage would receive the most views and be on the far left in the green, while this page might be on the far right in the yellow, as would most of Wikipedia's articles. The same could be said for Amazon's book inventory or Netflix's movie inventory. The total volume of low popularity items exceeds the volume of high popularity items.