Instead of relying on personal identifiers, platforms lean on contextual signals, on-device processing, and cohort-based bidding models that preserve relevance without exposing identity. Clean rooms and privacy-preserving APIs let advertisers match outcomes without sharing raw data, while conversion modeling fills gaps left by restricted cookies. Server-side bidding also reduces leakage of sensitive signals. Attribution becomes less deterministic and more statistical, using incrementality tests and modeled conversions rather than exact user paths. The result is a trade-off between precision and compliance.