Reddit's ChatGPT citations fell 86% in four days, and the change was OpenAI's, not Reddit's

A fan-out query is the retrieval a system runs before it writes a word of the answer ^[6]. Promptwatch reports that the share of ChatGPT's fan-out queries carrying a `site:` operator went from roughly 0.37% to 16.8% on August 8, which is about a 45-fold increase and just over 16 percentage points ^[5][13]. A domain-scoped query narrows what can come back to whatever lives on the named domain, so Promptwatch reads the pattern as a retrieval adjustment inside ChatGPT rather than anything aimed at Reddit ^[7].

The arithmetic does not close cleanly, and that is the interesting part. If 16.8% of fan-out queries now carry the operator, then 83.2% still do not ^[16]. Yet Reddit came out of it holding 13.6% of its former citation share, down 3.31 percentage points ^[12]. A change touching roughly one query in six removed 86% of one domain's citations ^[3][16]. Either those domain-scoped queries were doing most of the citation-generating work, or more than one thing moved on August 8. Promptwatch calls its data provisional and says collection problems cannot be ruled out, so it does not claim to know which ^[9].

The windows deserve the same scrutiny. The baseline runs 21 days, the post-change reading covers 4, and the six days from August 8 to August 13, immediately after the retrieval change, sit in neither ^[14]. The 86.4% figure is a three-week average compared against a long weekend ^[3][14].

Meanwhile the Google products Promptwatch tracks moved too, gradually: about 11% off Reddit's citation share in AI Overviews, about 30% in AI Mode ^[8]. That makes ChatGPT's drop roughly 2.9 times the size of AI Mode's and 7.9 times AI Overviews' ^[15]. Reddit's content did not degrade in three different ways at once, which supports the retrieval reading. It also means the slower declines have some other cause, and that Reddit's standing as a citable source was already drifting down before anyone flipped a flag on August 8 ^[8].

For anyone doing the measuring, the operative distinction is that a page can be crawlable and indexed and still go uncited, because indexing governs whether a document can be found and retrieval governs whether it is looked for ^[10]. Every check Promptwatch recommends sits on the publisher's side of that line: diff the Reddit URLs cited before and after August 14, confirm important pages are indexed for domain-scoped queries, test `site:` retrieval directly, watch GPTBot, re-run the fan-out analysis per model ^[11]. Those will tell you whether your own plumbing is the problem. None of them tells you whether the model will fan out toward your domain next month, and there is no notification when it stops.

Which is the actual finding here. Citation share behaved like an asset for three weeks and like a tenancy on the fourth. The page is yours; the retrieval path to it belongs to whoever ships the next configuration change.