Google Algorithm Update Timeline

Targeted thin content, duplicate content, and low-quality sites. Affected approximately 12% of search results on launch. Sites with thin pages, keyword stuffing, or high ad-to-content ratios saw major ranking drops. The signal later became part of Google's core algorithm.

Penalised link spam including paid links, link farms, and over-optimised anchor text. Ran periodically until 2016 when it became real-time. Webmasters affected had to submit disavow files and wait months for recovery. Fundamentally changed off-page SEO practices.

A complete rewrite of Google's core search algorithm focused on conversational search and semantic understanding. Rather than matching keywords, Hummingbird understood the intent behind a full query — enabling better results for long-tail, question-based searches. Laid the groundwork for voice search.

Google's first use of machine learning as a ranking signal. RankBrain interprets ambiguous, never-seen-before queries by finding related concepts and delivering relevant results without exact keyword matches. Became the third-most-important ranking signal within months of launch.

Bidirectional Encoder Representations from Transformers — allowed Google to understand the full context of words in a query, including the role of prepositions. Affected 10% of English queries at launch. Especially impactful for nuanced, conversational queries where word order changes meaning entirely.

Made user experience metrics (LCP, FID, CLS) official ranking signals via the Page Experience Update. Combined with HTTPS, mobile-friendliness, and safe browsing signals. Pages in the "Good" Core Web Vitals range gained a ranking advantage. Prompted major industry investment in performance optimisation.

Targeted content created primarily for search engines rather than people. Introduced a site-wide signal — if a site has significant amounts of unhelpful AI-generated or thin content, the whole domain is demoted. Particularly impacted affiliate, programmatic SEO, and news sites. Expanded and strengthened in 2023.

Google's AI-powered spam detection (SpamBrain) neutralised large-scale link schemes including expired domain abuse and link exchanges. Ran alongside October 2023 core update. Reduced the effectiveness of manipulative link building significantly — many link-based SEO tactics lost their ranking power.

The largest core update in Google's history, running alongside a spam update for 45 days. Targeted low-quality, unoriginal content at scale — specifically programmatic and AI-generated content farms. Removed approximately 40% of low-quality results. Many affiliate and content sites lost 50–90% of organic traffic. HCU signal was integrated into core.

Google rolled out AI Overviews (formerly Search Generative Experience) to all US users and later globally. AI-generated summaries now appear for 60%+ of queries, reducing clicks on organic results for informational queries by an estimated 15–30% for position 1. Created new optimisation opportunity: being cited within the AI Overview. Fundamentally changed SEO strategy for informational content.