What is first-party data in advertising?
First-party data is information a company collects directly from its own customers and audience, such as purchase history, website and app behavior, email subscriptions and loyalty-programme details. Because it comes from a direct relationship, usually with consent, it is more accurate and more privacy-resilient than third-party data bought from brokers, and is central to targeting after cookie restrictions.
First-party data differs from second-party data (another company's first-party data shared through a partnership), third-party data (aggregated by brokers) and zero-party data (information customers volunteer, such as preferences).
Advertisers activate first-party data through a CDP, hashed email matching on platforms, data clean rooms and lookalike audiences. Publishers use theirs to offer seller-defined audiences. Retailers turned it into the retail media boom.