Google March 2026 Core Update Targets AI Content with New 'Information Gain' Metric

Google launched its March 2026 Core Update on March 27, with a projected rollout completing by April 10. The update has already affected over 55% of monitored websites and introduces a 'Gemini 4.0 Semantic Filter' that enforces a new 'Information Gain' metric — penalising pages that add nothing beyond what the top 100 results already cover and rewarding content backed by first-hand testing, original data, proprietary research, and verified authorship. The update is the third major algorithm change in four days and represents Google's most direct assault yet on AI-generated derivative content.