What is a Google Ads Publisher ID? Publisher IDs (format: pub-XXXXXXXXXXXXX) uniquely identify Google AdSense/AdX accounts. They appear in ads.txt files to authorize ad serving on websites.

How Are Publishers Ranked? Rankings are based on domain count — how many websites in the Majestic Million dataset use each publisher ID. Higher domain counts indicate wider publisher reach and market influence.

Why Does Market Share Matter? Market share percentages reveal competitive positioning in the ad tech ecosystem. Dominant publishers often represent major media companies, ad networks, or popular website platforms.