Bezos figured that what had been useful to Amazon would be valuable to other businesses, too. The company opened Mechanical Turk as a public site in November 2005. Today, there are more than 1,00,000 “Turk Workers” in more than 100 countries who earn micropayments in exchange for completing a wide range of quick tasks called , human intelligence tasks (HITs), for various companies.

Harnessing the collective wisdom of crowds isn’t new. It is employed by many of the “Web 2.0” social networks like Digg and Del.icio.us, which rely on human readers to select the most worthwhile items on the Web to read. But creating marketplaces of mercenary intelligences is genuinely novel.

PriceGrabber.com, a comparison shopping site, uses Mechanical Turk to match images to the product pages. “Harnessing the power of this enormous, decentralized work force allows us to obtain images for a wide variety of items in a fraction of the time it would have taken to do it ourselves,” said Sagar M. Jethani, PriceGrabber’s director of content development and community.

Mechanical Turk’s customers are corporations. Amazon makes money from Mechanical Turk by charging companies 10 per cent of the price of a successfully completed HIT. For simple HITs that cost less than 1 cent, Amazon charges half a cent.

—JASON PONTIN