Algorithm Change Log — AI Search Platform Updates

This page tracks every significant algorithm update, platform change, and industry shift that affects AI search visibility. From Google core updates to ChatGPT ad launches, each entry explains what changed and why it matters for AI search optimisation. This page is updated weekly.

2026

March 27, 2026 — Google March 2026 Core Update

Google rolled out the March 2026 core update with a stated focus on three signals: originality, usefulness, and credibility. This update continued Google's shift toward rewarding content that demonstrates genuine expertise rather than content that simply covers a topic comprehensively.

Impact on AI search: Sites that lost organic rankings also saw reduced presence in AI Overviews, reinforcing the finding that 93.67% of AI Overview citations come from top 10 organic results. Original research, proprietary data, and first-hand experience were rewarded. Aggregated or rewritten content from other sources was penalised.

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March 2026 — Google March 2026 Spam Update

Running alongside the core update, the March 2026 spam update targeted manipulative practices across all languages globally. Previous spam updates had been English-focused; this was the first to apply penalties uniformly across all language versions of Google.

Impact on AI search: Sites using AI-generated content at scale without editorial oversight were particularly affected. Gemini and AI Overviews both reduced citations from sites flagged in this update, suggesting a shared quality signal between Google Search and Google's AI products.

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February 5-27, 2026 — Google Discover Core Update

Google ran a Discover-specific core update targeting clickbait and headline-content misalignment. Sites using sensational headlines that did not match the actual content were suppressed in Discover feeds. The update also rewarded content with strong headline-to-content alignment.

Impact on AI search: While Discover is not directly an AI search platform, the headline-content alignment signal appears to influence AI Overviews as well. Pages with misleading or exaggerated titles saw reduced AI citation rates during this period.

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February 2026 — ChatGPT Ads Launched

OpenAI launched advertising in ChatGPT, reaching an annualised run rate of $100 million within weeks. Ads appear as sponsored results within ChatGPT responses at a $60 CPM rate. This marked the first time a major AI chatbot introduced paid placements alongside organic citations.

Impact on AI search: The introduction of ads creates a two-tier visibility system in ChatGPT — organic citations and paid placements. For AI search optimisation, organic visibility remains the foundation, but brands now need to consider whether competitors are paying for visibility in queries where they previously appeared organically.

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February 2026 — Google Added "Authors" Section to Search Central Docs

Google updated its Search Central documentation to include a dedicated "Authors" section, providing guidance on how to properly mark up author information for search. This formalised Google's stance on author entity signals as a ranking and quality factor.

Impact on AI search: Author entity signals feed directly into Gemini and AI Overviews. Properly implemented author markup (using Person schema, linking to author profiles, consistent NAP across the web) helps Google's AI verify content credibility and attribute expertise correctly.

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January 16, 2026 — Cloudflare Acquires Astro

Cloudflare completed its acquisition of Astro, the web framework. This brought the Astro framework under the Cloudflare ecosystem, integrating it with Cloudflare Workers, Pages, and edge computing infrastructure.

Impact on AI search: The acquisition signals the growing importance of edge-rendered, performance-optimised sites for AI crawlers. AI bots (GPTBot, PerplexityBot, ClaudeBot) benefit from fast server responses and clean HTML — both strengths of Astro's architecture. Sites built on Astro/Cloudflare may see improved crawl efficiency from AI bots.

2025

December 2025 — Google December 2025 Core Update

The December 2025 core update focused on experience dilution and content depth over content length. Google explicitly rewarded pages that demonstrated deep expertise on a narrow topic over pages that covered broad topics superficially. Long-form content that lacked genuine depth was penalised.

Impact on AI search: AI Overviews began favouring shorter, more focused pages over comprehensive pillar pages. This marked a shift — AI platforms prefer content that answers a specific question authoritatively rather than content that tries to cover an entire topic. Agencies reporting improved AI visibility saw it in clients who had broken large pages into focused, expert-driven pieces.

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August 2025 — Google August 2025 Spam Update

The August 2025 spam update targeted expired domain abuse — the practice of buying expired domains with existing authority and redirecting them to new content. Sites using purchased expired domains to artificially boost authority were penalised.

Impact on AI search: AI platforms rely on domain authority as one signal for citation quality. The expired domain crackdown meant that artificially inflated domain authority no longer translated into AI search visibility. Brands that had used expired domain strategies saw their AI citations drop alongside their organic rankings.

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March 2025 — Google March 2025 Core Update

The March 2025 core update fully integrated E-E-A-T (Experience, Expertise, Authoritativeness, Trustworthiness) as a core ranking signal rather than a quality guideline overlay. This was the first update where E-E-A-T moved from being an assessment framework to being directly embedded in the ranking algorithm.

Impact on AI search: This update established E-E-A-T as the foundation for AI citation quality. Gemini, AI Overviews, and to a lesser extent ChatGPT all use E-E-A-T signals when selecting which content to cite. First-hand experience, verifiable expertise, and trustworthiness signals became essential for AI search visibility — not just desirable.