# Ahrefs: ChatGPT triggers a web search on just 14% of prompts

Published: 2026-10-12T09:05:19.552Z · Source: Ahrefs Blog (https://ahrefs.com/blog/query-fan-out-chatgpt/)
Source date: 2026-10-12
Flags: Ahrefs study — vendor-published
Entities: chatgpt, openai

Ahrefs analyzed 66.6 million free, logged-out ChatGPT-5.6 Luna responses from August and September 2026 and found only 14.4% triggered a web search at all, averaging 1.6 fan-out queries — the sub-queries ChatGPT runs while answering — each. Of the resulting 15 million fan-out queries, 6.8% used the site: operator to search one domain directly, spread across roughly 116,000 sites; apple.com, ikea.com and nike.com topped the list by mentions. That 6.8% sits far below the 76% that a smaller Seer Interactive study measured on a narrower prompt set in September — Ahrefs' own comparison table attributes the gap to sample scope and prompt mix, not a methodology error in either study.

A second, separate Ahrefs dataset tracking actual citations (2.4 to 3.8 million ChatGPT answers a month, via Brand Radar) confirms the citation collapse this wire has tracked since August at larger scale: Reddit's share fell from roughly 1 in 5 answers in March to 1 in 43 by late September, an 88% drop, and Wikipedia fell from 1 in 7 to 1 in 35, down 80%. Over the same stretch, the combined citation share of OpenAI's 17 licensed content partners more than doubled from 7.5% in March to a July peak of 15.8%, before easing to 12.5% by late September. Reddit itself still ranks ninth among the domains ChatGPT searches directly with the site: operator — Ahrefs reads this as the model still fetching Reddit for opinions while citing it less.

Why it matters: Most AEO effort is built around the moment ChatGPT performs a live web search; this data says that moment happens on only one answer in seven, which means what the model already associates with a brand likely matters more than anything a page can do in the other six.

## What this answers

**How often does ChatGPT actually search the web?**

Only 14.4% of 66.6 million free, logged-out ChatGPT-5.6 Luna responses triggered a web search in August and September 2026, averaging 1.6 fan-out queries each when it did, per Ahrefs.

**How often does ChatGPT use the site: search operator?**

6.8% of its 15 million fan-out queries used the site: operator to search one domain directly, spread across roughly 116,000 domains, per Ahrefs — far below the 76% a smaller, narrower Seer Interactive study found in September, a gap Ahrefs attributes to sample scope rather than a wrong number.

**Is ChatGPT citing Reddit and Wikipedia less often?**

Yes. Per Ahrefs' Brand Radar citation data, Reddit's share of ChatGPT citations fell from about 1 in 5 answers in March 2026 to 1 in 43 by late September (down 88%), and Wikipedia fell from 1 in 7 to 1 in 35 (down 80%), while OpenAI's licensed content partners rose from a 7.5% combined citation share to a July peak of 15.8%, easing to 12.5% by late September.


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