Prediction markets

Wikipedia

Also known as information markets, decision markets, idea futures, and virtual markets, prediction markets are speculative (i.e., betting) markets created for the purpose of making predictions. Assets are created whose final cash value is tied to a particular event (e.g., will the next US president be a Republican) or parameter (e.g., total sales next quarter). The current market prices can then be interpreted as predictions of the probability of the event or the expected value of the parameter.

... [CLB: Lots of information on, examples of, and links to prediction markets.]