Companies are waging an invisible data war online. And your phone might be an unwitting soldier. Retailers from Amazon and Walmart to tiny startups want to know what their competitors charge. Brick and mortar retailers can send people, sometimes called "mystery shoppers," to their competitors' stores to make notes on prices. Online, there's no need to send people anywhere.

Get in-depth coverage of current and future trends in technology, and how they are shaping business, entertainment, communications, science, politics, and society.

Advertisement