What source categories show up most in AI answers? | Trakkr Research

Reference and social are the clearest named categories, while the long tail still absorbs most citations.

Methodology: Built from the live citation index backing Trakkr Research, using 8,777,687 citations across 208,567 unique domains observed between October 3, 2025 and April 17, 2026.

Direct Answer

Mostly, the long tail absorbs citations at 84.51%, while reference and social are the clearest named categories. Reference sources hold 6.75%, social holds 3.82%, reviews hold 0.89%, and docs hold 0.20%.

What this means

Operators must allocate resources based on category share to determine what content types to publish, refresh, or measure next for optimal AI visibility.

Evidence table

Metric Value Why it matters
Reference category share 6.75% Reference sites are the largest named category in the current index.
Social category share 3.82% Social sources matter materially, led by YouTube, Reddit, and LinkedIn.
Review category share 0.89% Reviews are smaller in raw share but disproportionately commercial.
Docs category share 0.20% Docs are cited less often overall, but they show up in technical query classes.
Long-tail share 84.51% Most citations are spread across a very large long tail of domains.

Frequently Asked Questions

How much of the citation share belongs to the long tail?

Most citations are spread across a very large long tail of domains, accounting for 84.51% of the total share.

Which named category receives the highest citation share?

Reference sites are the largest named category in the current index, holding a 6.75% share.

Are review sites significant despite their low overall share?

Reviews hold a 0.89% share, which is smaller in raw share but disproportionately commercial.

What to do next

Related pages

Continue through the same study cluster.

Data & Sources