Amazon's Mechanical Turk used in Fossett search

Amazon.com's Mechanical Turk is enlisting human eyes to help in an online search for missing adventurer Steve Fossett.

Mechanical Turk is a Web service hosted by Amazon that lets anyone combine human intelligence with computer programs. The site aims to make up for a specific failure that persists in computers. "Humans still significantly outperform the most powerful computers at completing such simple tasks as identifying objects in photographs -- something children can do even before they learn to speak," the site explains.

Friends of Fossett have set up a project on Mechanical Turk that could help identify the location of his airplane. Fossett set out in the plane in Nevada on Sept. 3 and hasn't been heard from since.

Anyone can visit the Mechanical Turk site and lend a hand. Instructions on the page ask participants to view satellite images within Google Earth of the region where Fossett is thought to be. If they see anything that might resemble the airplane, they can mark the satellite image as containing an object that should be looked at more closely.

Participants are asked to mark an image if they are at all suspicious that it contains something of interest. The project also cautions people not to worry that missing a detail will be tragic, because many people will look at the same image. Marked images will be further examined by experts.

Mechanical Turk was also enlisted in the hunt for Jim Gray, a prominent computer scientist who went missing after setting off on his sail boat earlier this year. He has not been found.

The Fossett effort also includes airplane and helicopter searchers.

Fossett is well-known for being the first person to fly a plane solo around the world without refueling and also for making it around the world in a balloon. He has set 115 world records or world firsts, has swum the English Channel and completed the Iditarod, a dog sled race in Alaska, according to his Web site.

While people helping to hunt for Fossett and Gray are volunteers, other Mechanical Turk projects pay participants, usually less than $0.25 per task.

Mechanical Turk isn't the only online service that relies on human intelligence. ChaCha.com, a search engine launched last year, uses human "guides" to provide search results. A user inserts a search term and a remote worker searches for the answer, sending links to Web pages back to the user. The guide may be an expert in the subject the user is searching for so may be able to find better results than other search engines, according to ChaCha.

Mahalo.com is another search site that uses people to compile results for common search terms. Workers weed out spam sites, pages with overbearing advertising and sites that use information without giving appropriate credit to the source.