Brick-and-mortar stores are scrambling to understand their customers. Facing intense competition from online retailers who can gather extensive data about user behavior, traditional retailers have also started tracking customers’ in-store activities. From special equipment that picks up cell phone signals in the area to software that identifies people in video footage, brick-and-mortars are learning more about their customers — often without them knowing. As these tools have become more popular, they have begun to draw the attention of privacy regulators and advocates. The Federal Trade Commission, for example, held a meeting on mobile device tracking to discuss the risks to consumer privacy, and the Future of Privacy Forum established a program to allow consumers to opt out of mobile device tracking. Academic researchers and journalists continue to investigate the implications of in-store tracking for consumer privacy.