There is, the proverb says, nothing new under the Sun. But what Anderson has dubbed "the long tail", whose tail grows ever longer, seems to be new. Online retailing means that conventional economic models are breaking down. This is most obvious in music, where hits no longer have power they used to. For example, apparently every one of the 2 million tracks on iTunes has sold at least once. But "half of the 10,000 top CDs at Wal-Mart don't sell once a quarter". And now there is even a "long tail" in the demand for something as basic as flour, bought online. The mass market, Anderson argues, "is turning into a mass of niches".

The sub-title's "endless" and "unlimited" are hyperbolic and, although it's growing quickly, only 10 per cent of retailing is done online. But Anderson shows how fecund the "long tail" is. In crisp, brisk prose, once you've grasped such buzzwords as Powerclaw, Anderson adduces the likes of Long Tail Libations, created by America's largest brewer to sell special beers online. From cricket to Christianity, the tail is getting longer and the head shorter.

The most interesting sections for anyone aged over 30 are those on traditional retailing. Anderson's analysis of the humble supermarket shelf is fascinating. It's not a shelf. It's a science. For the rest, the 3-D printers or the proliferating pornography, the mind boggles.

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