Full Answer

Meta Advantage+ is an AI-driven campaign system that replaces manual targeting with algorithmic audience discovery. Its learning depends entirely on the quality and volume of conversion signals it receives. When purchase events are systematically missing — blocked by ad blockers (31% of users), restricted by Safari ITP, or lost to mobile browser closures — Advantage+ optimizes toward an incomplete sample of your customer base.

The effect compounds over time. Early in a campaign, Advantage+ runs a broad exploration phase looking for converters. It rewards the audiences where it found conversions — but those are the audiences whose purchases it could track. Safari users and ad-blocker users generated real purchases that never reached Meta. The AI learns to de-prioritize those audience segments, concentrating delivery toward Chrome desktop users who happen to allow tracking.

Adding or improving CAPI fixes this at the source. Server-side purchase events bypass browser restrictions entirely. With more complete conversion data, Advantage+ builds lookalike audiences from the full buyer pool, allocates budget more accurately, and exits the learning phase faster — typically requiring the 50 optimization events per week threshold, which is harder to reach when 30–40% of real conversions are invisible.