The markets below are so-called "double auction" markets. As market managers, we define and list "contracts" which have a value to be determined by some future event. For example, we might open an "Avian Influenza Market" and list a contract in it which will have a value of $1.00 if the first case of a human H5N1 infection in the U.S. occurs by January 1, 2010, and $0.00 if that event does not occur. Participating "traders" make offers to buy and sell those contracts at prices of their choosing, prices which accord with their beliefs about the likely outcomes of that event. When a buyer's price matches or exceeds the price offered by a seller, a trade happens. These trading prices can properly be interpreted by the traders and visitors alike as the "markets" prediction of the likelihood of occurrence of the event in question.
Hotspot Markets are a more like a survey than a market, but a survey with a twist. First, it is an interactive survey. Participants get to see responses of others and can change their responses as they wish. And second, it comes with rewards for getting the answers right. We'll ask a question, like "which of these 13 states will see the biggest increase in syphilis this month. You make your predictions by placing tokens on a map. At the end of the month we'll give you a lottery ticked for each token you have on one of the "winning" [sic] states, and conduct a lottery to see who wins the prize. During the month, social and health care workers and policy setting officials will be able to see the aggregate predictions and thus be alerted to potential problem areas in time to make a difference.