In short, the Long Tail describes the narrowing of option with specification of search.
This idea can be quite useful for any business wishing to promote an obscure or unique item or service. If the searcher knows specific details or "key word" for what they are looking for, their chances of finding exactly what they want are greatly increased. Both business and consumer benefit immensely from the effects of the Long Tail.
An article by Chris Anderson gives some excellent examples of how the Long Tail works. The article highlights the importance of diverse entertainment and product options. Only a small number of people actually seek out mainstreamed items. Robbie Vann-Abdid, the CEO of a jukebox company which offers over 150,000 titles has incredible statistics that prove this point. Out of 10,000 top titles 99% of them are listened to at least once a month. This goes to show that variety and specificity are key elements to success in the ever expanding and abundant, new commerce we operate in.