What ChatGPT cited in 240 answers#
In Prefer’s study of 80 questions about AI search, ChatGPT cited Google’s own documentation more than any other source. On 13 September 2026 we asked ChatGPT those questions (23 about choosing tools), three times each, through the DataForSEO API with web search on (gpt-5.6-luna). Its 240 answers carried 731 citations.
| Source | Answers citing it (of 240) | On tool questions |
|---|---|---|
| Google Search Central docs | 58 | 3 |
| arXiv papers | 44 | 17 |
| TechRadar | 27 | 22 |
| OpenAI Help Center | 23 | 1 |
| Bing Webmaster help | 22 | 3 |
| Google Help Center | 18 | 3 |
| 16 | 15 | |
| Google blog | 16 | 0 |
| Ahrefs | 14 | 6 |
A third of ChatGPT’s citations (239 of 731) went to pages published by Google, OpenAI, Microsoft, Anthropic or Perplexity. On the same questions, where those pages are on topic, Gemini gave them 1.8% of its citations, Perplexity 1.5% and Claude none.
Broader samples rank other sites first: Ahrefs’ September 2026 all-topics tracker puts Reddit first (16.8% of citations among top sources) and Forbes fourth; Profound’s study of about 730,000 ChatGPT.com conversations from late 2025 lists Wikipedia, then Reddit and Reuters.
What the other engines say ChatGPT cites#
Asked this question, 9 of 12 answers named Reddit and 9 named Wikipedia, three each from Perplexity, Gemini and Claude. The same nine named Forbes and Reuters. On our AI-search questions, ChatGPT cited neither Forbes nor Reuters. No engine cited Reuters and only 11 of all 960 answers cited Forbes, so this reflects the topic.
All three ChatGPT answers said no public ranking exists. One said: “There isn’t a publicly available ranking of the websites ChatGPT cites most often.” All three listed official sources first, including company documentation: closer to what it cited on these questions than Reddit and Wikipedia are.
Reddit showed up on tool-buying questions#
Fifteen of the 16 ChatGPT answers that cited Reddit came from the 23 questions about choosing, pricing or comparing AI visibility tools. That is 15 of 69 answers, against 1 of 171 elsewhere.
Perplexity cited Reddit in 98 of 240 answers and Gemini in 93, mostly on questions not about tools. Claude cited it in none.
Why our August study put Reddit first#
In August, Reddit was ChatGPT’s most-cited source on all 25 software-buying queries, 30.3% of 118,245 citations. It used DataForSEO’s LLM Mentions database:
| August study | This study | |
|---|---|---|
| Questions | 25 “best X” software queries | 80 about AI search, 23 about tools |
| Instrument | A database pooling many stored answers per query | Each question asked three times through an API |
| What we counted | Each domain’s share of all citations | Answers citing a domain at least once |
| Limits | One run on one day, US English | One day, one topic, API rather than the app |
Our July API study found one Reddit or YouTube citation from ChatGPT across 47 buyer questions. We have not tested which difference drives the gap.
How to find the sources ChatGPT cites for your prompts#
Prefer tracks the domains each answer cites for your own prompts, across five AI engines. To do it by hand:
- Write 10 to 50 buyer prompts and tag each as a how-to question or a product choice (how many prompts to track). Done when every prompt has a tag.
- Pick one surface and keep it fixed: the app with search on (read the sources each answer links) or the API (log the cited URLs it returns). Done when it is written down.
- Run each prompt at least three times and rank cited domains within each tag. Three is a floor, not a tested minimum: two runs shared only 37% of domains on average. An overall ranking would have hidden the Reddit pattern above. Done when a new round of runs adds no domain to any tag’s top 10.
- Mark the domains you can reach. You cannot edit Google documentation; you can pitch a review site or join a cited forum thread under your own name. Done when each has an owner and a next step.
- Re-run the same prompts on a schedule (how often to check). Done when you have two dated snapshots. If a domain you worked on never appears, try the next one.
Disclosure: Prefer sells AI visibility tracking, so we have a stake in you measuring this. For a baseline on your own prompts, run a free AI visibility audit.
Sources
- On 13 September 2026 we asked ChatGPT (gpt-5.6-luna through the DataForSEO API, web search on) 80 questions about AI search, three times each. Its 240 answers carried 731 citations. The domains cited in the most answers were developers.google.com (58), arxiv.org (44), techradar.com (27), help.openai.com (23), bing.com (22), support.google.com (18), reddit.com (16), blog.google (16) and ahrefs.com (14). (Prefer research note: which sources ChatGPT cites (2026-09-19), dated research note)
- In our September 2026 study of 80 questions about AI search, 239 of ChatGPT's 731 citations (32.7%), in 92 of its 240 answers, went to pages published by Google, OpenAI, Microsoft, Anthropic or Perplexity. On the same questions, such pages were 1.8% of Gemini's citations (38 of 2,074), 1.5% of Perplexity's (68 of 4,674) and none of Claude's (0 of 1,100). (Prefer research note: which sources ChatGPT cites (2026-09-19), dated research note)
- In our September 2026 study of 80 questions about AI search, answers citing reddit.com, out of 240 per engine: Perplexity 98, Gemini 93, ChatGPT 16, Claude 0. Fifteen of ChatGPT's 16 came from the 23 questions about choosing, pricing or comparing AI visibility tools (15 of 69 answers); the other 57 questions produced one (1 of 171 answers). (Prefer research note: which sources ChatGPT cites (2026-09-19), dated research note)
- Asked 'Which sources does ChatGPT cite most often?' on 13 September 2026, 9 of 12 answers named Reddit and 9 named Wikipedia, three each from Perplexity, Gemini and Claude. The same nine named Forbes and Reuters, and six named Business Insider. On our 80 questions about AI search, ChatGPT cited none of the three in its 240 answers; no engine cited Reuters or Business Insider, and Forbes appeared in 11 of all 960 answers, so the absence reflects the topic. All three ChatGPT answers said no public ranking of its most-cited sources exists, and cited only OpenAI's own pages. (Prefer research note: which sources ChatGPT cites (2026-09-19), dated research note)
- Prefer's August 2026 study read the DataForSEO LLM Mentions database, which pools many stored ChatGPT answers per query, for 25 B2B software buyer queries. Reddit was ChatGPT's most-cited source on all 25, 30.3% of 118,245 source citations, followed by Wikipedia (13.8%), TechRadar (9.6%) and Forbes (7.3%). It was one run on one day (19 August 2026), US English, so the figures are directional. (Prefer Reddit citation study, method note (2026-08-19), dated research note)
- In our September 2026 study, when ChatGPT answered the same question more than once, two runs shared on average 37% of the domains either run cited (206 pairs of runs). The figure was 96% for Perplexity, 68% for Claude and 35% for Gemini. (Prefer research note: which sources ChatGPT cites (2026-09-19), dated research note)
- In our September 2026 study, in 99 of its 240 answers at least one of ChatGPT's reported web searches used the site: operator to search a single website, such as site:help.openai.com (14 answers), site:developers.google.com/search (16) or, on tool questions, site:peec.ai (22). None of Gemini's or Claude's reported searches did; Perplexity's searches were not reported. ChatGPT cited Wikipedia in 6 of 240 answers, four of them the same article, about Writesonic. (Prefer research note: which sources ChatGPT cites (2026-09-19), dated research note)
- Prefer's July 2026 study of 47 buyer questions across 8 industries (gpt-4o via API, one run) counted one Reddit or YouTube citation from ChatGPT, which answered 29 of the 47 without searching the web. (Prefer AI citation study, method note (2026-07-10), dated research note)
- Ahrefs' ChatGPT tracker (Brand Radar, United States, all topics, September 2026 edition, updated 2 September 2026) puts www.reddit.com first at 16.8% mention share, a domain's citations as a share of the summed citations of the top sources, en.wikipedia.org second at 7.0% and www.forbes.com fourth at 3.1%. Ahrefs: The 50 most-cited websites in ChatGPT (September 2026)
- Profound's analysis of about 730,000 ChatGPT.com conversations with at least one web citation (US, English, October to December 2025) found Wikipedia at 5% of all citations and in 18% of conversations with citations, Reddit at 3% and 13%, and Reuters third at 1% and 4%. Profound: How ChatGPT sources the web (3 February 2026)
- Prefer sells AI visibility tracking, so we have a commercial stake in you measuring your own prompts rather than relying on a published ranking. It runs your prompts on ChatGPT, Gemini, Perplexity, Google AI Overviews and Google AI Mode and shows which domains each answer cites. Prefer pricing (our product)
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