On May 15, 2026, Google released its first official AI Optimization Guide and stated plainly: schema markup is not required for AI Overviews. Two years of GEO vendor pitches just got contradicted. What actually decides citation now?
Google's Preferred Sources feature lets users designate trusted websites for AI answers. For ecommerce brands, earning that designation means higher visibility in AI Overviews and AI Mode — a new trust signal that works differently from traditional SEO rankings.
After Google's March 2026 core update, schema markup shifted from a SERP display trigger to an AI citation trust signal. Products with complete structured data — GTIN, attributes, shipping details, return policy — appear in AI-generated answers at 2.5x the rate of products with basic schema.
Google's AI-generated summaries are eating into organic clicks. Here's what's actually happening, which queries are affected, and what cross-border sellers can do about it now.