Predictive Markets for the World Cup?
The pricing of these 'shares' on almost all of the various electronic markets are based on the probabilities of a particular team winning. In theory, one could use the information gleaned from these sites in order to make predictions on how the various soccer/football teams will do during the World Cup. At the very least, one can study what type of information affects prices/subjective probabilities and where the consensus of opinion seem to be headed toward.
The World Cup market is one example of a predictive market. Predictive (or prediction or information) markets have been set up by economists (and others) in order to use market mechanisms to determine the most likely outcomes of political contests, sporting events, and other non-economic events. For the most part, these markets have done a pretty good job (at least better than the alternatives) at making predictions. A good overview of prediction/predictive markets can be found in the following working paper on Justin Wolfer's website: http://bpp.wharton.upenn.edu/jwolfers/Papers/PredictionMarkets(Palgrave).pdf