In Brandweek: A good overview of work that is underway in a number of companies. These methods " ... are now standard for the larger packaged goods firms like Procter & Gamble, Frito-Lay, ConAgra and Intel, which have been using them for years ... " .
For a simple example see IRI's model of a Wal-Mart.
Of particular interest is the use of more complex simulations that help drive the interaction between real consumer and virtual world. A way to measure some very predictive things in retail. And eventually simulating virtual consumer and a virtual world. That has also been tried in some insightful ways. There is a powerful possible integration here.