Data
GA4
Google's current analytics platform, built around an event-based data model. Includes ML-powered predictive metrics, cross-platform tracking, and BigQuery integration. Key limitations: aggressive data sampling at high volumes, limited historical lookback, and, critically in 2026, a structural inability to track AI-agent-referred traffic. When a user asks ChatGPT for a product recommendation, googles the brand name, and buys, GA4 attributes it to 'branded search' or 'direct traffic.' The AI agent's influence is completely invisible. This dark funnel blind spot means GA4 systematically understates the value of agent commerce and overstates the value of branded search.
Why it matters
It is where most teams read their blended truth, and its default attribution differs from every ad platform's, which is why the numbers never match.
In practice
Use it for on-site behaviour and cross-channel shape, not for channel credit. Reconciling GA4 to platform reporting is a task with no correct answer.
Related terms