PostHog is a comprehensive product analytics platform that tracks user events, analyzes behavior, and runs experiments. It provides funnels (user conversion paths), cohorts (user segments), session replay (playback of user sessions), feature flags (conditional feature rollout), and A/B testing capabilities. Unlike page-based analytics (Google Analytics), PostHog tracks event-level detail, giving deep insights into feature adoption and user engagement. PostHog is unique in being self-hosted and open-source, giving companies full control over data privacy and deployment. It integrates with product teams' codebases via SDKs and provides a SQL-like query language (HogQL) for custom analysis.