Cross-device retargeting involves re-engaging a user on a different device than the one they initially used. For example, if someone leaves an e-commerce site on their phone without making a purchase, the goal is to re-engage them when they browse on a computer, hoping to facilitate a conversion. This strategy can also work in the other direction, moving from a computer to a smartphone (or occasionally a tablet). By targeting the user on a mobile device, they can be reached more quickly without waiting for them to return to a computer. Implementing cross-device retargeting requires technology that can identify the user regardless of the device they are using. This approach is also commonly used in mobile app retargeting.