An AI citation is the inline source attribution that an AI answer engine displays alongside its synthesized response. ChatGPT typically cites 3-5 sources per answer; Perplexity cites 5-10; Google AI Overviews displays 3-10 source cards depending on query intent. Each citation is a link back to the source page, generating measurable referrer traffic for the cited site.
Citation share is the AEO equivalent of organic ranking. A site that is the #1 organic Google result but never cited by ChatGPT for the same query has effectively lost the AI-search surface. Conversely, a site that ranks #6 on Google but gets cited by Perplexity for half the relevant queries is winning the AI surface even while losing the classic one.
Measuring citation share has three practical methods: referrer-based attribution in your analytics (chatgpt.com, perplexity.ai, copilot.microsoft.com), manual probing (run 20-50 category queries against each engine and count appearances), and dedicated tracking via tools like SeoChatAI's free AI Citation Checker.
The high-leverage tactics to lift AI citation are direct-answer first paragraphs, FAQPage and HowTo schema, statistics with attributed sources every 150-200 words, recent dateModified, explicit AI-bot accessibility in robots.txt, and llms.txt declaration. Each compounds the others. A page that does all six can lift its citation share 3-5x within 2-3 weeks.