Storage Markets (powered by HSX, by the way):

[...] The Calibration Test provides a metric used in the discussion regarding the market’s ability to over or under forecast the. The Logarithmic Score is a metric that can be used to compare the quality of a market’s predictions against a so-called “expert”. The Entropy metric borrows the concept of decidedness from decision theory to give us insight into how well a market is incorporating new information into its prediction. [...]

I’m so impressed.

Appendix: Bo Cowgill assessing the Google’s internal prediction markets (circa end of 2005).