The Long Tail

Here is an excerpt from the book The Long Tail by Chris Anderson: "In 1988, a British mountain climber named Joe Simpson wrote a book called Touching the Void, a harrowing account of near-death in the Peruvian Andes. It got good reviews but, only a modest success, it was soon forgotten. Then, a decade later, a strange thing happened. Jon Krakauer wrote Into Thin Air, another book about a mountain-cämbing tragedy, which became a publishing sensation. Suddenly Touching the Void started to sell again".

The demand for Touching the Void was so high that it even outsold Into Thin Air after some time. But what exactly happened here? Well, it turns out that since both the books were based on the same theme, Amazon suggested that readers who liked Into Thin Air would also like Touching the Void. When people took in the suggestions they actually liked the book and as a result, wrote positive reviews which resulted in more sales ultimately leading to more recommendations and thereby kicking in a positive feedback loop. This is the power of recommendation systems.