First-party data
First-party data is data collected directly by the publisher from its own users (email, purchase history, declared preferences), without a third-party intermediary. It has become the central asset of post-cookie digital marketing.
In practice
Collecting first-party data goes through newsletter sign-ups, customer account creation, loyalty programs, and preference forms. Its quality — enriched, segmented data — surpasses third-party data in precision and durability. An email list of 10,000 engaged buyers holds more strategic value than a third-party advertising audience of 500,000 approximate profiles.