ID-less Targeting

ID-less targeting is the family of techniques for reaching audiences without per-user identifiers. The "cookies, gone or going" environment forces ad-tech to find substitutes, contextual signals (the content adjacent to the ad), cohort assignment (placing the user in a group rather than identifying them), supply-path signals (the publisher's first-party knowledge of its audience), and sensor-derived signals (the actual people in front of a DOOH or CTV screen).

Multiple ID-less standards have emerged. Google's Privacy Sandbox (TOPICS, Protected Audience API) replaces cookies with browser-resident cohort assignments. Permutive and similar players offer publisher-side cohort modeling. ID5, UID2, and RampID are "deterministic IDs", hashed-email systems that aren't cookies but still function as per-user identifiers if the user has consented. Each has different addressability/privacy trade-offs.

For DOOH, the sensor-derived path is the most powerful: the ad targets the actual audience composition currently in front of the screen, not a hashed user ID. Trillboards' cohort composition signal is ID-less by construction, it describes the group on-screen, not a single person, and never produces a per-person identifier.

Buyers building post-cookie strategies should treat DOOH not as a workaround but as a structural fit, the format never required user IDs to begin with.