Disclosure to users of who paid for an ad and why they were shown it, required by the EU's Digital Services Act for all ads on platforms and implemented as a control on most platforms. Paired with ad libraries, it makes targeting practices publicly inspectable.
Cite this entry:
Agency Echelon. "Ad Transparency." Agency Echelon Reference, reviewed September 2026. https://agencyechelon.com/reference/glossary/ad-transparency/