{
  "kind": "fact",
  "studySlug": "citation-sources",
  "slug": "the-current-index-tracks-millions-of-cited-urls",
  "title": "The current index tracks more than 3.6 million cited URLs",
  "description": "AI systems do not just cite domains. They return to a large but finite set of pages.",
  "lastUpdated": "2026-10-14",
  "lastTested": "2026-10-14",
  "sourceStudyUrl": "/trakkr-research/citation-sources",
  "sourceStudyTitle": "AI Citation Index",
  "claimIds": [
    "citation-sources:unique-urls",
    "citation-sources:total-citations"
  ],
  "relatedSlugs": [
    "answer:how-big-is-the-competitive-set-for-ai-citations",
    "answer:what-source-categories-show-up-most-in-ai-answers",
    "tracker:top-cited-domain-tracker"
  ],
  "methodologySummary": "Built from 80,769,585 citation appearances across 725,777 unique domains in the latest valid snapshot for 1,928 tracked brands, observed from October 3, 2025 to October 14, 2026.",
  "limitations": [
    "The index is a changing panel of tracked brands and prompts, not a random sample of all AI responses.",
    "Domain share is observational. It does not establish causal influence or reveal the full retrieval set.",
    "The hand-maintained source taxonomy is partial: 88.40% of citation appearances remain in “other”.",
    "Model attribution, response-level citation denominators, geography, raw prompts, and raw responses are not retained in the public aggregate."
  ],
  "keywords": [
    "AI citations",
    "citation sources",
    "AI source preferences",
    "domain authority in AI"
  ],
  "schemaHints": {
    "pageType": "Article",
    "includeDataset": true
  },
  "claim": "Trakkr currently tracks 3,687,821 unique cited URLs in the public citation index.",
  "supportingMetrics": [
    {
      "label": "Unique cited URLs",
      "value": "3.69M",
      "detail": "3,687,821 distinct cited URLs in the current snapshot."
    },
    {
      "label": "Citation appearances",
      "value": "80.8M",
      "detail": "80,769,585 appearances in the verified October 14, 2026 snapshot."
    }
  ],
  "whyItMatters": "URL breadth distinguishes the size of the observed evidence layer from domain-level concentration.",
  "citationBlock": {
    "quote": "Trakkr currently tracks 3,687,821 unique cited URLs in the public citation index.",
    "attribution": "AI Citation Index - Trakkr Research",
    "url": "https://trakkr.ai/trakkr-research/citation-sources/facts/the-current-index-tracks-millions-of-cited-urls"
  }
}