The Industry Standard has written up an overview on the prediction markets Google runs internally to improve their business decisions as well as learn how employees exchange information. A little tidbit caught my eye:

With about 1,500 employees making 80,000 "trades" over the past two and a half years, Google officials say it's the largest corporate experiment with prediction markets they are aware of.

The reason this caught my eye was because we have about a third of the users but have done about 180,000 trades in a year and a half. It's interesting to see the differences in trade volume between our groups of people.