The term “long tail” refers to all of the products that form the basis of a catalogue (items, photographs) that are sold in small proportions, but where the sum of these sales may, when combined, exceed the total sales of the most commonly sold products.

The long tail is suited to the web distribution model because of the fact the cost of putting an extra product online is marginal and that the virtual shelf space which is available to e-business sites is infinite, unlike the shelf space which is present in real life shops.