This article explores the influential yet underexamined role of media agencies in the digital media ecosystem, particularly within the news media sector. Media agencies shape the public sphere by directing advertising budgets toward specific platforms, thereby contributing to the platformization of media. Drawing on interviews and industry sources, the study shows that media agencies are heavily involved in digitizing, tracking, and commodifying audiences, while also recognizing the ethical concerns this creates. The article calls for greater political scrutiny and critical research into the democratic consequences of emerging value chains linking platforms, advertisers, media agencies, audiences, and news organizations.