In the simplest terms, cross-device tracking occurs when platforms, publishers, and ad tech companies trace consumer activity across connected devices. The Federal Trade Commission (FTC) recently released the Cross-Device Tracking: An FTC Staff Report, providing usage guidance and recommendations for this relatively new tracking method.

The cross-device tracking benefits include the ability to:

• Log into email or social media accounts from multiple devices.
• handoff from one device to another (e.g. one can start reading a book on one device and pick it up on another).
• Helps to fight against fraud, companies recognize users sign-on to devices with easy authentication methods.
• Personalize advertising by analyzing a consumer’s activities on all devices and then matching with offline behavior.

Many companies also use a probabilistic approach to extrapolate which consumer is using a device, even when a consumer is not logged into a service. This method of probabilistic tracking uses IP address matching. Typically, an ad platform places a cookie on a consumer’s browser, the cookie regularly includes the IP address of the device running the browser. Since the devices on the same local network often have the same public IP address, the ad platform can surmise that the devices using the same IP address, belong to the same household. It’s important to note that most of the probabilistic tracking companies, like third-party advertising, do not have a direct relationship with consumers nor have access to user agreements on data collection and data sharing.

Many consumers have little awareness of cross device tracking and the information captured from their smart televisions, health information from wearable devices, or offline shopping habits. Therefore, the FTC recommends the inclusion of four central practices for companies conducting cross-device tracking:

1. Transparency
   Companies should provide meaningful information to consumers about cross-device tracking activities to help inform consumer decisions about whether to use existing opt-out tools, or whether to stop using a site, app or service.

2. Choice
   Companies should offer consumer choices about how their cross-device activity is tracked. Consumers should be informed as to how the practices apply or are implemented.

3. Sensitive data
   Companies should stop cross-device tracking on sensitive topics, including health, financial, and children’s information, without consumers’ affirmative express consent.

4. Security
   Companies are required to maintain reasonable security, in order to avoid unexpected and unauthorized uses of data.All companies in the digital ecosystem, especially those that are consumer-facing, have a responsibility to inform consumers of third party and cross-device tracking companies being utilization on their site and apps.