http://www.businessweek.com/technology/content/oct2008/tc20081013_033687.htm "A Pool of Intelligence How did Wall Street know what would happen? It acted like a prediction market, a pool of intelligence that can foresee the future. Prediction markets are simply bets on ideas: What do you think something is worth, and more important, what will it be worth tomorrow? When groups of people bet on something, their combined intelligence is often remarkably prescient. British scientist Francis Galton was one of the first to notice this in 1906, when he observed 787 people at a country fair try to guess the weight of an ox after it was slaughtered. The average of all guesses was 1,197 pounds, only one pound less than the correct answer."