The adverts apparently use inaudible, high-frequency sounds to surreptitiously track a person’s online behaviour across a range of devices, including phones, TVs, tablets, and computers.
The ultrasonic pitches are embedded into TV commercials or are played when a user encounters an ad displayed in a computer browser.
Tablets and smartphones can detect the sound and browser cookies can now pair a single user to multiple devices and keep track of what TV commercials the person sees, how long the person watches the ads, and whether the person acts on the ads by doing a Web search or buying a product.
The Centre for Democracy and Technology wrote in recently filed comments to the Federal Trade Commission and apparently the FTC is somewhat worried.
Often, people use as many as five connected devices throughout a given day—a phone, computer, tablet, wearable health device, and an RFID-enabled access fob. Until now, there hasn’t been an easy way to track activity on one and tie it to another.
CDT officials wrote. “Cross-device tracking allows marketers to combine these streams by linking them to the same individual, enhancing the granularity of what they know about that person.”
The officials said that companies with names including SilverPush, Drawbridge, and Flurry are working on ways to pair a given user to specific devices. Adobe is developing similar technologies.