AI-driven media buying platforms will control 70% of global ad spend by 2028, but these systems are designed to serve platform interests (maximizing revenue) rather than advertiser interests (minimizing costs). Key risks include AI bias toward platform profitability and measurement fragmentation across platforms. Best practice: maintain human oversight, focus on business outcomes rather than vanity metrics, concentrate budget on major platforms (Google, Meta, Amazon), and use third-party measurement tools instead of relying solely on platform reporting.