We measured the drop ourselves. It is real, it is bigger than reported, and it is confined to one engine. But this is the second time in a year, and the last one reversed.
On 18 August, Promptwatch reported that Reddit's share of ChatGPT Search citations had collapsed by 86.4%, from 3.83% to 0.52%, in the four days between 14 and 17 August. The fall came in two steps: a smaller one on 8 August and a sharp one on the 14th. Reddit had been one of ChatGPT's most-cited domains for over a year.
Search Engine Land, Axios, Forbes and Search Engine Journal all carried it within days, and nobody could explain it. Promptwatch said plainly that it could identify when the shift happened but not why, and that it could not rule out a problem in its own data collection. The leading theory was that ChatGPT's use of the site: operator jumped to 16.8% of its background queries on 8 August, but the six-day gap before the real fall makes that a poor fit on its own.
There is also a precedent that got far less attention. In September 2025, Reddit's share of ChatGPT citations fell from roughly 7% to roughly 1%. Profound tracked it, the industry wrote it up, and within weeks it had rebounded to around 3%. The best available explanation was never a change in what ChatGPT valued: it was a change in how citation data could be collected. So we measured this one ourselves, across every client project we run.
What our own tracking panel found
1. Reddit's share of ChatGPT Search citations fell from 4.01% to 0.13%, a 96.9% drop, steeper than the 86.4% widely reported.
2. No other engine moved. Google AI Overviews rose 17%, AI Mode rose 5%, Perplexity more than doubled. We cannot reproduce the published Google declines.
3. Wikipedia went to zero in the same window. It ran at 0.88% of ChatGPT citations before, not one in 3,982 after. This is broader than Reddit.
4. ChatGPT now runs 2.4 sub-queries per answer instead of 1.2, up to 27% of them domain-scoped site: searches. None target Reddit.
This is one agency's panel: four projects, 55 prompts, two markets. Treat it as a second reading against the published numbers, not as a verdict.
Reddit's share of ChatGPT Search citations fell 96.9% in our data
Against an 18 July – 7 August baseline, Reddit accounted for 4.01% of ChatGPT Search citations, 169 of 4,214. In the 14–24 August window it accounts for 0.13%: five citations out of 3,982. That is a 96.9% relative drop, against the 86.4% in circulation.
Two things explain the gap, and neither means we are more right. Our post-change window runs ten days rather than four, so it captures the settled state rather than the first days of it. And our denominator is every citation, not a sample of top domains. In our windows the 25 most-cited domains cover under half of all citations, so a top-25 sample and a full count are measuring different things.
The decline came in two stages: 4.79% in 1–7 August, 1.71% in 8–13 August, 0.13% from the 14th. And it happened while ChatGPT's citation volume went up, from 201 to 362 citations per day, on flat response volume. Reddit was not squeezed out of a shrinking list. It was excluded from one that got longer.
Google AI Overviews and AI Mode did not follow
This is the useful part of running your own panel, and it is where our data parts company with the coverage. The published figures showed Reddit also declining in Google's AI products: around 11% in AI Overviews, 30% in AI Mode. We measured all five engines on the same prompts, on the same days, through the same collector.
• ChatGPT Search: share before 4.01%, share after 0.13%, citations 169 → 5, change −96.9%
• Google AI Overviews: share before 1.23%, share after 1.44%, citations 156 → 89, change +16.7%
• Google AI Mode: share before 1.04%, share after 1.09%, citations 231 → 110, change +4.8%
• Gemini: share before 0.49%, share after 0.21%, citations 10 → 5, change −56.6%
• Perplexity: share before 0.20%, share after 0.45%, citations 24 → 31, change +122%
Gemini's decline rests on ten citations falling to five, too small a base to carry weight. The other four rest on hundreds.
ChatGPT falls 96.9%. Google AI Overviews rises 17%, AI Mode rises 5%, Perplexity more than doubles from a low base. We are not claiming the published Google numbers are wrong. Our panel is small and weighted to Dutch and US markets, and Google's surfaces vary far more by query and locale than ChatGPT does, so different prompt sets can legitimately disagree. But within our panel there is no industry-wide effect to find. This is one vendor changing its retrieval, not a change in what Reddit is worth.
Which cuts both ways. Before the change, ChatGPT cited Reddit at three to five times the rate of every other engine. It was never a consensus that Reddit was an excellent source. It was one engine's unusual appetite for it, and that engine has now moved below the field.
Wikipedia also went to zero in ChatGPT's citations
The finding that has not appeared in the coverage: Wikipedia went from 0.88% of ChatGPT's citations to exactly none. Not one citation across 3,982. Trustpilot halved, from 0.50% to 0.23%. Reddit collapsed.
Meanwhile G2 rose 85% and Capterra held steady to the decimal. That combination rules out the simplest story. This is not ChatGPT turning against user-generated content, because G2 and Capterra are user-generated too. It is closer to this: ChatGPT stopped leaning on the general-purpose sources an open web search sweeps up, and started going directly to specific, structured, category-relevant destinations. Wikipedia and Reddit are what a broad search returns. G2 and Capterra are places you go on purpose.
Worth noting how large that is. In the industry datasets that tracked the September 2025 episode, Wikipedia was ChatGPT's single most-cited domain and Reddit was second. Ours is a niche commercial panel where Wikipedia was never going to top the list. It still went to zero.
Why ChatGPT stopped reaching Reddit: more sub-queries, and site: operators
Promptwatch extracts the background searches ChatGPT runs before answering. We pulled all 4,384 of ours, back to early May. Two things change on 8 August with no run-up.
Searches per answer roughly doubled. A median of 1.17 from May through 7 August, then 2.44 from the 8th. Domain-scoped queries appeared from nothing: exactly two site: queries in the 91 days before, then between 7.8% and 26.9% of every single day's sub-queries after.
Those 328 site: queries target 86 distinct domains, and not one is reddit.com. They are ecommerce platforms, software vendors, enterprise suites, and in the Dutch projects, individual contractors' own sites. No forum, no Q&A site, no encyclopedia.
The knock-on effect is concentration. ChatGPT's ten most-cited domains went from 31.4% of all citations to 42.0%; on the control engines that number barely moved. Two thirds of ChatGPT's citations now land on the 80 domains it targets by name, up from 56%. The count of distinct domains actually rose, from 450 to 501. The tail did not vanish, the head just grew much faster.
Being findable is no longer enough. You have to be the destination the engine decides to visit.
Is Reddit still shaping ChatGPT's answers without being cited?
This is the question that decides what you do. A citation is a display decision; retrieval is a substance decision. If Reddit still feeds the answer while losing its visible link, you would keep investing and simply stop measuring it by citations.
Three checks say it is genuinely gone from grounding, not hidden inside it:
• ChatGPT stopped asking for it. Exactly five sub-queries in our entire history append the word "reddit" to a search. The most recent is dated 7 July, six weeks before the citation drop.
• None of the domain-scoped queries target it. Zero of 328. If Reddit were being read but not credited, that is where it would show.
• It has left the language of the answers. Across 50 post-change answers the word "Reddit" appears zero times, as does every community-voice construction we tested for: "users report", "community consensus", "forum", "anecdotally". In 50 pre-change answers, 14% carried a Reddit citation.
What we cannot check: whether Reddit sits in OpenAI's retrieval set and is filtered out of the displayed citations. We cannot see that layer, and nobody outside OpenAI can. Reddit also remains in the training corpus, so it keeps shaping the model's priors regardless. That is invisible to every tracking tool, ours included, and it is not something anyone can optimise for.
What the Reddit citation drop means for your GEO programme
• Don't rebuild a strategy on a two-week reading. This is the second Reddit collapse in eleven months and the first one fully reversed. Source mixes churn, and we have watched them churn all year. The correct response to a two-week signal is to keep measuring it, not to tear up a programme.
• Reprice Reddit work, don't cancel it. Reddit holds its position in Google's AI surfaces, where our data shows no decline at all, and it still shapes what buyers believe before they open an assistant. What has died is the specific claim that Reddit activity earns ChatGPT citations. Report it against brand presence and Google AI coverage instead.
• Your own domain got more valuable. Roughly one in five ChatGPT sub-queries now goes straight at a named domain. If a competitor's site answers the scoped question and yours does not, you lose the citation without appearing in any ranking. Comparison pages, real pricing detail, specification tables, documentation that resolves a question in one fetch.
• Report citation share of voice, never citation counts. ChatGPT's citations per day rose about 80% in a fortnight. Any dashboard on raw counts showed a flattering rise during the exact two weeks a major source disappeared.
How we measured this, and the limits of a small panel
The panel is small. Four client projects, 55 tracked prompts, two markets, one agency. Primary comparison: 18 July – 7 August (21 days, 5,961 responses) against 14 – 24 August (11 days, 3,074 responses), with response volume flat at roughly 280 a day across both. ChatGPT figures are the ChatGPT Search surface; the control group is Google AI Overviews, Google AI Mode, Gemini, Perplexity Sonar Pro and Microsoft Copilot. Sub-query analysis covers all 4,384 fanout queries from 2,917 ChatGPT responses, 4 May to 24 August. All client names and domains have been removed.
Two measurement traps to avoid when tracking AI citations
• Top-25 truncation would make this analysis worthless. The 25 most-cited domains cover 48.7% of citations in the baseline window and 57.8% after it, so "Reddit is absent from the top 25" proves nothing on its own. Every figure here comes from the complete, uncapped URL list, verified by confirming the per-URL counts sum exactly to the reported window totals.
• Substring matching over-counts Reddit by 40%. Searching the string "reddit" in the recent window returns seven citations rather than five. Two are ecommerce app-store pages carrying st_source=reddit tracking parameters. Parse the host, never the string.
Limits on what this data can claim
• Correlation, not causation. The sub-query jump, the site: operator appearing, the citation-volume rise and the Reddit collapse all land on 8 August, and no control engine shows any of it. That is consistent with a ChatGPT-side retrieval change, but the data contains no explicit exclusion of Reddit, and "sub-queries became domain-targeted and displaced open-web results" fits equally well.
• The two-stage pattern is unexplained. One platform shows Reddit declining steadily from 8 August; the other shows a brief spike on 9–10 August before the collapse on the 14th. Both agree on the endpoint. Neither explains why the sharpest fall came six days after the retrieval change.
• A panel this size cannot support claims about how the effect varies by industry, and we are not making any. The direction replicates across all four projects; the magnitude differs, and with one or two projects per category that difference is not evidence of anything.
• Two weeks is a short window for a conclusion about a system that has changed its source mix repeatedly this year. We will publish an update if it moves.
Sources
Public coverage read for this piece. All figures attributed to PromptMarketing come from our own tracked panels, pulled 24 August 2026.
1. Why Did ChatGPT Stop Citing Reddit? Inside the August 2026 Citation Collapse · Promptwatch
2. Reddit Citations Are Dropping in ChatGPT · Promptwatch
3. Reddit's ChatGPT Search citations fell 86% in four days · Search Engine Land
4. Why Reddit's ChatGPT Citation Drop Isn't Fully Explained · Search Engine Journal
5. Reddit fades from ChatGPT citations · Axios
6. Reddit Nearly Vanishes From ChatGPT Citations · Forbes
7. Reddit's ChatGPT Citations Fell 86%. It Happened Before and It Came Back. · Aivo, on the September 2025 precedent
PromptMarketing is Europe's GEO / AI-Search agency. We help brands get found, cited, and recommended across ChatGPT, Claude, Gemini, Perplexity, and Google AI Overviews, measuring how AI engines perceive a brand, then engineering content, technical foundations, and authority to improve it.