Third-Party Data
Third-party data is audience information collected by companies that have no direct relationship with the people it describes. These data providers aggregate signals from many sources, then package and sell the result to advertisers and marketers for targeting, audience expansion, and enriching existing records with demographic or firmographic detail.
Marketers buy third-party data to reach prospects beyond their own contacts, fill gaps in account profiles, or build broad targeting segments through advertising platforms and data marketplaces. In B2B it often takes the form of firmographic, technographic, or contact databases used for prospecting and enrichment.
Reliability and privacy are the key concerns. Because the data is collected at arm's length, accuracy varies and consent can be unclear, and the deprecation of third-party cookies has reduced its reach in web advertising. Many teams now treat it as a supplement to first-party data rather than a foundation, and verify it carefully against privacy regulations.
Last updated: 14 June 2026