The Google Blog has a rather un-interesting post on how Google uses predictive markets to gleen important information from their collective minds. Microsoft Research has been running predictive markets for some time now. I personally participated in one predicting certain facts around the release of the product that eventually became the WDK Driver Test Manager. Of more interest than the Google blog entry is the fact that MIT has eliminated the best public predictive market.
Is anyone aware of other public predictive markets I can participate in?