A Device ID is a string of numbers and letters that identifies every individual smartphone or tablet in the world. It is stored on the mobile device and can be retrieved by any app that is downloaded and installed. Apps typically retrieve the ID for identification when talking to servers.
In the context of mobile advertising, a device ID will be one of two things. Depending on your operating system, the Device ID will either be used as the identity which advertisers, marketers and other services will track when looking for a particular type of device, or for services in Google Play:
Device IDs are the easiest way to identify mobile users, as they allow you to track individual devices. This not only reveals certain user behaviour (which can be aggregated to identify trends) but also allows you to put users into cohorts based on understood identifiers such as geographic region or device. Essentially, if you’re able to track a user’s Device ID, you are able to create a much clearer picture of how they behave.
If a publisher allows you to track Device IDs from their platform, it’s easy to see whether users have looked at your ad and whether they clicked to install. It can also show how a user interacts with your app after install. This is because you can track the Device ID throughout the process. Testing users for a better understanding of a cohort (such as for creative, or ad optimization) also improves due to the use of unique user IDs.
The Adjust platform generates internal IDs, as well as registering device IDs. We do this because device IDs are only available intermittently, and are not consistently tracked as if there was one single, unchanging number. Because of this, we can create a more consistent user profile.
Our generated IDs also include some extra rules that make them better as a privacy-compliant analytics package, mainly because they’re not personally identifiable in the same way as IDFAs. This means the privacy of your users is safe.