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Brian O'Kelley

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Brian O'Kelley is the Co-Founder and CEO of Apostra, the agentic advertising company formerly called Scope3. He co-founded Scope3 with Anne Coghlan to cut the carbon emissions of digital advertising and led its September 2026 rename and pivot to AI agents that buy and sell media. He previously co-founded AppNexus and led it as CEO from 2007 to 2018. Before that he was CTO of Right Media, where he invented the first ad exchange; Yahoo! later acquired Right Media.

Last updated Oct 6, 2026 by the ATDb Editorial Team · Connections updated Oct 6, 2026

In the news
Role
Co-Founder and CEO
Company
Apostra
Based
New York, New York, United States
Boards
1
Connections
7

AI-drafted from public sources13 sources cited

Years in industry
20 years

Bio

Brian O'Kelley is the Co-Founder and CEO of Apostra, the agentic advertising company formerly called Scope3. He co-founded Scope3 with Anne Coghlan to cut the carbon emissions of digital advertising and led its September 2026 rename and pivot to AI agents that buy and sell media. He previously co-founded AppNexus and led it as CEO from 2007 to 2018. Before that he was CTO of Right Media, where he invented the first ad exchange; Yahoo! later acquired Right Media.

Career

Roles with a cited source. All linked roles are in the Roles tab.

Expertise & education

Expertise

Programmatic AdvertisingAd Exchange TechnologySupply-Side Platforms (SSP)Demand-Side Platforms (DSP)AdTech InfrastructureSustainable AdvertisingCarbon Measurement in MediaReal-Time Bidding (RTB)

Education

  • B.S. Computer Science, Princeton University

Speaking topics

Decarbonizing digital advertisingThe history and future of programmatic advertisingSustainable media supply chainsAdTech infrastructure and open internet economicsEntrepreneurship in AdTech

Recognition

Notable achievements

  • Invented the first ad exchange at Right Media, a foundational innovation that gave rise to programmatic advertising
  • Co-founded and led AppNexus as CEO from 2007 to 2018, growing it into one of the world's leading independent programmatic platforms
  • Drove Right Media's acquisition by Yahoo! following the ad exchange invention
  • Co-founded Scope3 to address the carbon footprint of digital advertising supply chains

Awards

AdExchanger Industry Award — Industry LeaderInducted into the AdTech Hall of Fame (various industry recognitions)

Publications

  • Regular contributor and commentator in AdExchanger, Digiday, and industry trade press on programmatic and sustainability topics
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