What is Longtail?

The Long Tail is a retailing concept describing the niche strategy of selling a large number of unique items in relatively small quantities – usually in addition to selling fewer popular items in large quantities. The concept was popularised by Chris Anderson in an October 2004 Wired magazine article, in which he mentioned Amazon.com and Netflix as examples of businesses applying this strategy. Chris Anderson elaborated the Long Tail concept in his book The Long Tail: Why the Future of Business Is Selling Less of More...

The distribution and inventory costs of business successfully applying this strategy allow them to realize significant profit out of selling small volumes of (har dot find) items to many customers instead of only selling large volumes of a reduced number of popular items.
The total sales of this large number of "non-hit items" is called THE LONG TAIL.
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, crowdcasting, peer-to-peer), economic models, and marketing (viral marketing).