The Wall Street Journal has an article about a worker fired last month for intercepting New York Times reporter's phone calls and reveals he was part of a much larger, sophisticated surveillance operation which snooped on employees, critics, stockholders and even a consulting giant. From WSJ:

As part of the surveillance, the retailer last year had a long-haired employee infiltrate an anti-Wal-Mart group to determine if it planned protests at the company's annual meeting, according to Bruce Gabbard, the fired security worker, who worked in Wal-Mart's Threat Research and Analysis Group. The company also deployed cutting-edge monitoring systems made by a supplier to the Defense Department that allowed it to capture and record the actions of anyone connected to its global computer network. The systems' high-tech wizardry could detect the degree of flesh-tone on a viewed Internet image, and alerted monitors that a vendor sharing Wal-Mart networks was viewing pornography.