Intra-device is particularly applicable to the mobile world, and refers to the ability to recognize a user within the same device, but across mobile web and in-app. Recall that 3rd party cookies are often deactivated in many devices in the mobile web, and unless the user does not clickthru on an ad or affiliate link, there are few alternatives to recognizing the user outside of probabilistic identifiers. When the user goes to a mobile app, on the other hand, there is often a way to recognize the user through deterministic identifiers (IFAs).
Identity Resolution Services that can bridge the gap and recognize users as they move from mobile web to in-app can map out and include the intra-device journey, which can be woven into an overall understanding of the user’s cross-device journey