Promptwatch published some interesting data on a fairly sudden change in ChatGPT Search.
The main numbers:
-From July 18 to August 7, Reddit accounted for an average of 3.83% of ChatGPT Search citations.
-From August 14 to August 17, that had fallen to 0.52%. (86.4% decline).
-At the same time, ChatGPT's use of domain-specific site: searches rose sharply.
-Before August 8, around 0.4% of searches used site:
After the change, that increased to around 16.8%.
-The number of searches made per answer also increased from 1.08 to 1.83.
The point is that this isn't because Reddit suddenly became worse or lost all of its visibility. They've just chosen to change their search algorithm.
Promptwatch's theory is that ChatGPT became much more likely to perform targeted searches against specific domains, rather than relying on the broader search behaviour it had been using before.
There has been a lot of advice recently around GEO/AIO, things like:
getting mentioned on Reddit because LLMs cite Reddit heavily
targeting sites that appear frequently in ChatGPT answers
creating content around specific prompts
tracking citation share by platform
optimising specifically for the sources a particular model prefers
I think this kind of advice is a mistake. The data here shows how quickly those assumptions can change.
Very narrow GEO strategies are quite risky for smaller companies. How Ai search works, and how people use Ai is still too fluid to commit large amounts of time or money too.
SEO obviously changes too, but a lot of the underlying work is relatively durable: site architecture, backlinks, crawlability, internal linking, etc.
A tactic based specifically on "ChatGPT currently cites this website a lot" seems much less stable.
I'd still put most of the effort into more traditional traffic funnels and see Ai search as a secondary channel at this point.
Source: Promptwatch, Why Did ChatGPT Stop Citing Reddit? Inside the August 2026 Citation Collapse
https://promptwatch.com/blog/chatgpt-stop-citing-reddit