First-party Data

First-party data is information that a brand has collected through a direct relationship with its consumers. This data is therefore owned by the advertising brand. Facebook, Apple, Google, and AppLovin are all examples of advertising brands.  

When a brand runs an ad campaign, it uses its first-party data to target specific audiences. For example, if you purchase items through an eCommerce app, the eCommerce company will have contact information, purchase history, preferences, and possibly other data it has collected that it can use to show relevant ads and offers to you.