The U.S. government's recently disclosed program of electronic surveillance may rely on "pattern recognition" software to rapidly filter very large volumes of phone calls and e-mails, according to some media reports. Nello Cristianini, associate professor of statistics at UC Davis, is an expert in pattern recognition and can discuss the state of the art in business and scientific applications, and how this technology might be used in electronic surveillance. Pattern recognition tools are already widely used in the private sector, he notes. For example, Internet sites such as Amazon and Google use such tools to identify purchasing habits and suggest additional items that customers might want to buy. (Cristianini has no affiliation with any security agency.)