Abstract: An online system receives a request from a third-party application for a content item to be delivered to a user of a user device, the request including a device identifier corresponding to the user device used to access the third-party application. In order to deliver a targeted content item, the online system accesses inference model to infer an identity of the user, based upon device usage parameters based upon the received request, historical data associated with the device identifier, or an indication of activity associated with the device identifier on the online system or one or more first-party applications.

Abstract: An online system receives a variety of identifiers associated with a user of the online system and generates a federated list of identifiers for the user that includes each of the received identifiers. Identifiers may be browser identifiers, device identifiers, Internet protocol address, personally identifiable information, or a user identifier of a different online system. For each identifier in the federated list of identifiers, the online system generates metadata information such as a confidence score indicating a degree of certainty that the identifier can be used to accurately identify the user of the online system. The online system aggregates features associated with the identifiers in the federated list of identifiers to generate a comprehensive user profile of the user and uses the comprehensive user profile to better serve the user.

Abstract: An online system receives a request from a third-party application for a content item to be delivered to a user of a user device, the request including a device identifier corresponding to the user device used to access the third-party application. In order to deliver a targeted content item, the online system accesses inference model to infer an identity of the user, based upon device usage parameters based upon the received request, historical data associated with the device identifier, or an indication of activity associated with the device identifier on the online system or one or more first-party applications.

Abstract: An online system receives a variety of identifiers associated with a user of the online system and generates a federated list of identifiers for the user that includes each of the received identifiers. Identifiers may be browser identifiers, device identifiers, Internet protocol address, personally identifiable information, or a user identifier of a different online system. For each identifier in the federated list of identifiers, the online system generates metadata information such as a confidence score indicating a degree of certainty that the identifier can be used to accurately identify the user of the online system. The online system aggregates features associated with the identifiers in the federated list of identifiers to generate a comprehensive user profile of the user and uses the comprehensive user profile to better serve the user.