Google Analytics 4 represents a fundamental shift from Universal Analytics. GA4 uses an event-based data model instead of session-based tracking. Every interaction is an event with associated parameters. Enhanced measurement automatically tracks scrolls, outbound clicks, and video engagement. User identification across devices uses Google signals. The analysis hub provides advanced exploration capabilities. Funnel analysis visualizes user through key flows. Path exploration shows user navigation patterns. Segment overlap identifies audience intersections. Predictive metrics forecast purchase probability and churn. Audiences can be exported to Google Ads for targeting. DebugView helps validate tracking implementation. BigQuery export enables custom analysis at scale. GA4 is privacy-centric with no IP logging and consent mode. The learning curve is steeper than Universal Analytics. Migration requires careful planning and parallel setup. Events should be planned with consistent naming conventions. GA4 is designed for the future of privacy-focused analytics. Understanding the event-driven model is key to successful implementation.