PINDROP BLOG

The Silent Tracking Beacon in Your TV Ads

It turns out that the weird guy in your office who keeps telling you that his TV is spying on him isn’t totally insane. Well, he might still be insane, but his TV also might be spying on him.

An Indian company called SilverPush has developed a technology that allows advertisers to track users across multiple devices through the use of inaudible sound beacons. The signals are sent by TV ads and mobile devices that have the SilverPush SDK installed will pick up the beacons and identify the device as belonging to the same person as the TV sending the signal. It’s a subtle, little-known technique and one that has privacy advocates and others worried about the implications for users.

Cross-device tracking is a controversial topic in the privacy community, but for advertisers, marketers, and the technology companies that provide their tools it’s the holy grail. It gives companies the ability to gather intelligence on not just what content users are consuming, but how they’re doing so, where they are when they’re watching it or reading it, and what device they’re consuming the content on. That’s incredibly valuable data for marketers but experts are concerned about not just what data is gathered, but the way in which it’s collected and, most importantly, what users know about the collection process.

SilverPush has been deploying its ultrasonic multi-device tracking for about a year now, and regulators and technologists have begun to express concern about its implications for consumers.

“The user is unaware of the audio beacon, but if a smart device has an app on it that uses the SilverPush software development kit, the software on the app will be listening for the audio beacon and once the beacon is detected, devices are immediately recognized as being used by the same individual. SilverPush states that the company is not listening in the background to all of the noises occurring in proximity to the device. The only factor that hinders the receipt of an audio beacon by a device is distance and there is no way for the user to opt-out of this form of cross-device tracking,” a group of lawyers and technologists from the Center for Democracy and Technology said in a letter to the Federal Trade Commission in advance of the FTC’s conference on cross-device tracking in November.

SilverPush has been deploying its ultrasonic multi-device tracking for about a year now, and regulators and technologists have begun to express concern about its implications for consumers.

However, an executive from SilverPush told Forbes that the company could not sync its audio beacon with users’ phones.

“We do not match desktop to mobile,” Piyush Bhatt of SilverPush said to Forbes.

The privacy concerns surrounding the use of this kind of technology are wide-ranging and thorny. Users are generally unaware of the existence of tracking technologies such as SilverPush’s Unique Audio Beacon and the ways in which it can tie together their TV viewing, Web browsing, and other habits. Those data points can give marketers the ability to put together a detailed picture of a user and her activities, preferences, and movements.

That makes targeted marketing a simple task and also makes things such as Do Not Track even less useful than they already are. Web sites don’t need to bother with dropping a simple cookie on a user’s machine when they can use an ultrasonic signal to tie together the target’s laptop, TV, and mobile phone. That’s next-level device and user tracking and this likely is only the beginning.

Experts at the W3C, the body that sets rules for the Internet, are paying attention, as well. The group’s audio working group has been discussing the topic on its mailing list in recent weeks, discussing whether there’s a need for a permission for Web audio to play, or some similar safeguard.