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llms.txt GeneratorHow concentrated is the AI citation landscape?
The top three domains account for 5.82% of citation appearances, while the index spans 725,777 unique domains and 3.69 million cited URLs. That is a visible head followed by a very broad tail.
The key numbers.
- Top three domain share
- YouTube, google.com, and Reddit together account for 5.82%.
- 5.82%
- Unique domains
- Distinct normalized domains in the current brand snapshots.
- 725,777
- Unique cited URLs
- 3,687,821 distinct cited URLs in the current snapshot.
- 3.69M
- Unclassified share
- Domains outside the current named source map remain in “other”.
- 88.40%
Concentration is measurable, but the public index does not establish why a domain is selected or whether the same pattern holds outside the tracked panel.
The evidence.
Source
AI Citation Index
| Measure | Result |
|---|---|
| Top three domain share YouTube, google.com, and Reddit together account for 5.82%. | 5.82% |
| Unique domains Distinct normalized domains in the current brand snapshots. | 725,777 |
| Unique cited URLs 3,687,821 distinct cited URLs in the current snapshot. | 3.69M |
| Unclassified share Domains outside the current named source map remain in “other”. | 88.40% |
Population and method
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.
Where the evidence stops
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.
What to do with this
- Audit the domains that already dominate your category and decide which ones are realistic citation targets.
- Build source-worthy pages for the query shapes where AI is already citing third parties.
- Treat reference, review, and social sources as part of your AI visibility surface, not as noise.
This answer matters because it turns a study finding into an operating rule teams can use when they decide what to publish, refresh, or measure next.
Questions about this answer.
Cite this answer.
Source study: Citation Sources“The top three domains account for 5.82% of citation appearances, while the index spans 725,777 unique domains and 3.69 million cited URLs. That is a visible head followed by a very broad tail.”
Mack Grenfell · How concentrated is the AI citation landscape?
AI Citation Index · Trakkr Research · Updated 14 October 2026