Advertisers Embrace Agentic Audience Vector Targeting

Evgeny Popov writes on March 2, 2026, that programmatic advertising is shifting from Boolean segment IDs to dense embedding-based User Context Protocol (UCP) vectors. He explains publishers, data providers, and measurement partners can contribute context, intent, and exposure vectors that compose at impression time, letting agents score impressions via dot product and avoid combinatorial explosion. The change enables finer-grained, per-impression bidding and relevance.