# AI Ranked > AI Ranked is a publication about AI search: generative engine optimization (GEO), answer engine optimization (AEO) and AI visibility. It covers how ChatGPT, Gemini, Claude, Perplexity, Microsoft Copilot and Google AI Overviews/AI Mode retrieve and cite sources. Every factual claim links to a primary source. Published by Arobis AI. Pages lead with a short, self-contained answer, followed by key takeaways, sourced sections, an FAQ and a numbered source list. Content may be quoted with a link. ## Guides - [What is generative engine optimization (GEO)?](https://airanked.ai/guides/what-is-generative-engine-optimization): Definition, origin in the 2023 Princeton-led GEO paper, tactics with evidence and a 30-day plan. - [How AI engines choose which sources to cite](https://airanked.ai/guides/how-ai-engines-choose-sources): Retrieval stacks and citation patterns for ChatGPT, Perplexity, Gemini, Google AI Mode, Claude and Copilot. - [GEO vs AEO vs SEO](https://airanked.ai/guides/geo-vs-aeo-vs-seo): Definitions, a side-by-side comparison and when to prioritize each. - [How to measure AI visibility](https://airanked.ai/guides/measure-ai-visibility): Prompt sets, mention rate, citation rate, share of voice and tracking tools. - [AI crawler user agents and robots.txt](https://airanked.ai/guides/ai-crawlers-robots-txt): Every major AI crawler, its operator and purpose, with robots.txt recipes. - [What is llms.txt?](https://airanked.ai/guides/llms-txt): The proposal, the format, adoption and evidence on whether engines read it. ## Research and reference - [Which AI crawlers do top websites block?](https://airanked.ai/research/ai-crawler-access-report): Original study of robots.txt files on 261 major sites, with the dataset as CSV. - [AI search statistics](https://airanked.ai/research/ai-search-statistics): Sourced statistics on AI search usage, citations, referral traffic and crawlers. - [AI search glossary](https://airanked.ai/glossary/): 40 GEO and AEO terms defined. - [AI search news](https://airanked.ai/news/): Dated, sourced news on AI search engines and the AI visibility industry. ## Buyer's guides - [The best GEO agencies](https://airanked.ai/guides/best-geo-agencies): Twelve GEO agencies compared on services, pricing and fit. - [Best free AI visibility checkers](https://airanked.ai/guides/best-ai-visibility-checkers): Ten free checkers compared. - [The best AI visibility tools](https://airanked.ai/guides/best-ai-visibility-tools): Eleven AI visibility platforms compared on engines, price and limits. - [Profound alternatives](https://airanked.ai/guides/profound-alternatives): Eight alternatives to Profound and when each fits. - [The best AEO agencies in 2026: 10 answer engine optimization firms compared](https://airanked.ai/guides/best-aeo-agencies): The best AEO agencies for 2026: 10 answer engine optimization firms compared on fit, published prices, contract terms and AI results, plus what AEO costs. - [The best AI SEO agencies in 2026: 10 firms that optimize for Google and AI answers](https://airanked.ai/guides/best-ai-seo-agencies): The best AI SEO agencies for 2026: 10 firms that optimize for Google and AI answers, compared on fit, pricing, engines covered and real AI results. - [Peec AI alternatives: 8 tools and when each one beats Peec](https://airanked.ai/guides/peec-ai-alternatives): Peec AI alternatives compared on vendor-published prices, engines and cost per AI answer: Scrunch, Profound, AthenaHQ, SE Ranking, ZeroRank and 3 more. - [AthenaHQ alternatives: 8 tools and the credit math behind the switch](https://airanked.ai/guides/athenahq-alternatives): AthenaHQ alternatives compared: what 3,600 credits really buy, then Peec AI, Scrunch, Profound, ZeroRank, Rankscale and 3 more on price, engines and fit. - [AI Mode tracker: 11 tools that track Google AI Mode, checked on vendor pages](https://airanked.ai/guides/ai-mode-tracker): Which tools really track Google AI Mode? 11 AI Mode trackers checked on vendor pages, with prices, plan limits, how tracking works and what Search Console shows - [AI Overview tracker: 11 tools to track Google AI Overviews, plus what Search Console shows free](https://airanked.ai/guides/ai-overview-tracker): AI Overview trackers compared: 11 tools checked on vendor pages, keyword vs prompt tracking, prices, and what Search Console's AI report shows for free. - [ChatGPT rank trackers: 11 tools that track your brand in ChatGPT, compared](https://airanked.ai/guides/chatgpt-rank-tracker): ChatGPT rank trackers compared: 11 tools that track brand mentions, citations and position in ChatGPT, with prices, answer volumes and how each collects data. - [Perplexity rank trackers: 11 tools that track your citations and brand in Perplexity](https://airanked.ai/guides/perplexity-rank-tracker): Perplexity rank trackers compared: 11 tools that track citations, source position and brand mentions in Perplexity, with prices, answer volumes and test tips. - [How to rank in ChatGPT and get recommended for buyer prompts](https://airanked.ai/guides/how-to-rank-in-chatgpt): How to rank in ChatGPT and get recommended for buyer prompts: how it picks brands, an 8-step plan with done criteria, a worked example and how to measure it. - [GEO audit checklist: 32 pass/fail checks for AI search visibility](https://airanked.ai/guides/geo-audit-checklist): A GEO audit checklist with 32 pass/fail checks for AI search: crawler access, indexing, citable pages, entity facts and measurement, with time and tools. ## Free tools - [Citability grader](https://airanked.ai/tools/citability-grader): Scores a page 0 to 100 on signals that make AI engines quote it. - [AI crawler robots.txt checker](https://airanked.ai/tools/robots-txt-ai-checker): Shows which AI bots a robots.txt allows or blocks. - [llms.txt generator](https://airanked.ai/tools/llms-txt-generator): Builds a spec-compliant llms.txt file. - [Schema generator](https://airanked.ai/tools/schema-generator): Generates FAQPage, Article, Organization and HowTo JSON-LD. ## Optional - [About AI Ranked and editorial standards](https://airanked.ai/about/)