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Brian O'Kelley
Co-Founder and CEO at Scope3
Pioneering programmatic advertising infrastructure and leading Scope3's mission to reduce the carbon footprint of digital media
Last updated May 31, 2026 by the ATDb Editorial Team
Bio
Brian O'Kelley is Co-Founder and CEO of Scope3, where he is focused on decarbonizing digital advertising. He previously co-founded and led AppNexus as CEO from 2007 to 2018, and before that served as CTO of Right Media, where he invented the first ad exchange — an innovation that helped give rise to programmatic advertising and led to Right Media's acquisition by Yahoo!.
Previous Roles
CEO and Co-Founder
AppNexus (2007-2018)
CTO
Right Media (2003-2007)
EVP, Technology
Yahoo! (post Right Media acquisition) (2007-2007)
Expertise
Programmatic AdvertisingAd Exchange TechnologyReal-Time Bidding (RTB)Supply Chain TransparencyAdTech InfrastructureSustainability in AdvertisingCarbon Emissions MeasurementVenture-Backed Company Scaling
Education
- B.S., Computer Science, Dartmouth College
Notable Achievements
- Invented the first ad exchange at Right Media, leading to a ~$850M acquisition by Yahoo! in 2007
- Co-founded and led AppNexus to a $1.6 billion acquisition by AT&T in 2018
- Raised over $350 million in venture capital for AppNexus
- Co-founded Scope3 in 2020 to bring carbon accountability to the digital advertising supply chain
- Widely credited with laying the technical and commercial foundation for the modern programmatic advertising ecosystem
Awards
AdExchanger's Most Influential Person in AdTech (multiple recognitions)Inducted into the AdTech Hall of Fame (industry recognition)
Speaking Topics
The history and future of programmatic advertisingSustainability and decarbonization of the ad supply chainSupply chain transparency and efficiency in digital mediaEntrepreneurship and company building in AdTechThe environmental cost of digital advertising
Publications
- Frequent contributor and interview subject in AdExchanger, Digiday, and The Trade Desk industry forums
Board Memberships
Scope3 (as CEO/Co-Founder)
Connections