Roland Piquepaille writes: "A Columbia University computer science professor has co-founded a New York-based company named Sense Networks to sell tracking software to other companies. It is also distributing a free version of this software named Citysense, which shows on your cell phone where the wild things are happening in your own town. Citysense 'uses advanced machine learning techniques to number crunch vast amounts of data emanating from thousands of cell-phones, GPS-equipped cabs and other data devices to paint live pictures of where people are gathering.' Citysense is available today in San Francisco before being soon deployed in Chicago and five other U.S. cities. But read more for additional details showing how this system works."