Ronan Shields

Ronan Shields is one of the advertising technology industry's most authoritative investigative journalists, best known for his deep-dive reporting on programmatic advertising's systemic problems — including ad fraud, Made-For-Advertising (MFA) sites, supply path optimization failures, and arbitrage schemes that siphon value from advertisers. His work at Digiday has consistently broken stories that force industry-wide reckoning, making him a trusted voice for anyone trying to understand the opaque mechanics of the digital advertising supply chain. Shields joined Digiday after building a strong foundation in AdTech journalism at outlets including Adweek, where he covered programmatic and digital media. His reporting combines rare technical fluency in ad tech infrastructure — DSPs, SSPs, header bidding, bid stream dynamics — with a well-cultivated source network spanning buy-side, sell-side, and independent researchers. This combination allows him to translate complex, often deliberately obscured industry practices into accessible, impactful journalism. Over the course of his career, Shields has helped catalyze meaningful industry conversations around transparency and accountability in programmatic advertising. His investigations into MFA site proliferation and the economics of low-quality inventory have been cited by industry bodies and informed debates at major conferences. He is regularly referenced by practitioners, trade organizations, and platforms grappling with supply chain integrity issues.

• Broke multiple industry-defining investigations into MFA site economics and their impact on advertiser spend
• Reporting on programmatic supply chain opacity has been cited by industry bodies including ANA and IAB
• Established Digiday as a leading destination for programmatic accountability journalism
• Developed one of the most extensive source networks in AdTech journalism spanning DSPs, SSPs, agencies, and independent researchers

• Digiday
• Adweek