ChatGPT search now uses the site:operator at scale

Promptwatch is a company operating in the generative engine optimization space, which helps websites improve their visibility in responses from chatbots like ChatGPT. As part of its content marketing strategy, the company uses automated tracking to monitor chatbot replies and publish aggregate reports that reveal subtle design changes in products like ChatGPT, Claude, and Gemini.

Tracking data shows a significant shift in ChatGPT search behavior that aligns with the rollout of GPT-5.6. Previously, the daily percentage of search fanout queries using the site operator ranged between 0.3 and 0.5 percent. Following a brief dip in early August, this figure jumped dramatically to 16 to 17 percent by August 8. This change corresponds with an update announced by OpenAI to make the model more reliable with facts and provide more focused answers.

Observation of the tool suggests that the underlying search mechanism uses specific parameters like query, recency, and domains rather than relying on direct user input of the site operator. Subsequent tracking data from mid-August also indicates that ChatGPT significantly reduced its reliance on Reddit as a source in these searches, although leaked system prompts have not yet confirmed specific instructions regarding this reduction.