On January 28, a day of calm seas off the California coast, computer scientist Jim Gray left San Francisco on his 40-foot yacht Tenacious and made for the Farallon Islands, 43 kilometers beyond the Golden Gate Bridge, where he planned to scatter the ashes of his recently deceased mother. He failed to return that evening.
For the next four days, the U.S. Coast Guard searched the ocean around the Farallons but found no trace of him. Gray’s friends and colleagues, however, refused to give up. A technical fellow at Microsoft and a pioneer in the development of database systems and transaction processing, Gray, 63, was one of the most beloved figures in the computer science community. Executives at Amazon, Sun, Oracle, Google, Microsoft, and other companies organized an intense private search, even enlisting a plane owned by NASA–a close cousin of the U-2 spy plane–and a satellite operated by mapping company DigitalGlobe to collect thousands of new images of the areas to which Tenacious might have drifted.
Despite all this firepower, though, Gray’s friends knew they’d need outside help to analyze the images they accumulated. So engineers at Amazon divided the images into tiles, each showing a 300-by-300-meter square of ocean, and on February 2 they uploaded the tiles to Amazon Mechanical Turk, a website where people can earn micropayments in return for completing quick tasks–such as recognizing objects in photographs–that are difficult for computers but easy for humans. More than 12,000 volunteers spent five days scanning 560,000 images for blobs of white pixels that might be Tenacious. They spotted a candidate, but planes dispatched to that area found nothing.
Gray’s family called off the search on February 16, and his disappearance remains a mystery. But the massively distributed, Internet-based search for Tenacious, probably the largest effort of its kind in history, stands as a tribute to Gray and as a powerful example of the emerging technology of “human-assisted search.” Few of the technology’s applications are of the life-and-death variety. But having followed it for some time, I believe that it will soon become pervasive, and that it will dramatically change our assumptions and expectations about the search process and about the types of work that can be accomplished using the Internet. In contrast to the Web’s famous disintermediating effects in commerce, human-assisted search is a form of “reintermediation”–an acknowledgement that software isn’t always king, and that sometimes it helps to have a middleman.
Google’s remarkable success at taming the jungle of text-based Web pages fostered the dream among some researchers that all digital information could be indexed, organized, and comprehended algorithmically–that is, using software alone. If this dream ever comes true, it will be far behind schedule. Meanwhile, entrepreneurs at Web companies such as Amazon have begun to show how the brainpower of thousands of Internet users can be harnessed for specific tasks that remain beyond the capabilities of software.