When you visit a site like NYTimes, your browser fires off 30-80 ad requests before the page even finishes loading. Each request broadcasts your device type, screen size, approximate location, browsing context, and a bunch of behavioral signals to dozens of ad exchanges simultaneously. This happens in under 200 milliseconds. Advertisers bid on you in real time before you've read a single headline.
But it goes beyond your browser. Walk past a digital billboard in a mall or on a highway and your device's mobile advertising ID can be picked up through location data. That DOOH screen doesn't know your name, but it knows a device with your behavioral profile was within range. Later that day you might see a retargeted ad on your phone related to a store near that billboard. That's not a coincidence.
None of this requires your name, email, or any PII. The industry doesn't need to know who you are. It just needs enough signal to understand what kind of person you are. Device graph matching, probabilistic ID resolution, contextual signals, and cross-device tracking build a shadow profile that follows you across screens without ever knowing your real identity.
I built a tool that estimates how much money the industry has spent targeting you personally based on your age, screen time, and country. It uses real CPM rates and impression estimates from the industry.
The site uses GoatCounter for anonymous page view counts, it's open source, cookieless, collects no personal data, and doesn't even need a GDPR notice. Your inputs never leave your browser. I built it this way because I know what the alternative looks like from the inside.
attentionworth.com
Happy to answer any questions about how the ad tech pipeline actually works.