Retargeting is an advertising technique where mobile marketers and app developers target the audience who already showed an interest in the mobile app. There are two types of retargeting approaches in the mobile marketing ecosystem. 

The first one is about convincing users who visited an app page, or clicking an ad to install the app. For this type of retargeting, mobile marketers can prefer communication sources including:

• Push notifications
• Newsletters
• Social media engagement 
• In-app messages

The second one is called re-engagement where mobile advertisers focus on users who uninstall an app for good. In re-engagement campaigns, if the user re-install the app, this user is re-attributed to the previous attribution source. This is called reattribution.