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The off-site signals with the strongest published evidence are branded mentions across the web, presence in third-party review and comparison sites, community discussion, and earned editorial coverage. In Ahrefs' December 2025 analysis of 75,000 brands, branded web mentions correlated with AI visibility at 0.664 and YouTube mentions at 0.737, against 0.266 for Domain Rating and roughly 0.2 for raw backlink counts [2]. Muck Rack's July 2025 study of millions of AI-cited links found more than 95% of citations came from unpaid sources, and 85% of those were earned media [3]. Buyer-side survey data points the same way: 45% of B2B software buyers told G2 that a review-site citation is the most confidence-inspiring signal inside an AI answer [4]. Evidence quality varies sharply between these signals, though, and Google states that beyond being indexed and snippet-eligible there are "no additional requirements to appear in AI Overviews or AI Mode, nor other special optimizations necessary" [1].