Cellphones, traffic cameras, smart televisions - our every move is being recorded. Our phones track our location. Reward cards track our purchases. Computers track our Internet searches. But what happens to all of this information? Wal-Mart recently revealed that it hired big-data firms to collect and analyze the health-related data of its employees. This allows Walmart to send personalized messages to its employees in an effort to cut the company’s health care expenses. This is a risky move for employers because employees are protected by a host of federal and state discrimination and privacy laws. With access to this otherwise private information, employers may be tempted to use this information when making employment decisions. Tapping into big data serves companies well in marketing and advertising, but it can cross the line in other areas.