A change in specifications has been observed in OpenAI's AI search feature, "ChatGPT Search," regarding how it performs searches targeting specific sites. According to observations by Promptwatch, which tracks data metrics, ChatGPT Search began frequently using the "site:" operator to narrow searches to specific websites on 2026-08-08, with the proportion of such searches surging from 0.37% to 16.8% on the same day. Consequently, the citation share of Reddit, which had previously held one of the largest shares among sources, dropped from 4.14% as of April 2026 to 0.52% between August 14 and 17. OpenAI has not provided an explanation for the reason behind this specification change, and no similar sharp decline has been observed in Google's search engine.
Source: OpenAIがAI検索仕様を変更、Redditの引用シェアが数日で3.8％から0.5％に崩落 - Forbes JAPAN (Google News: OpenAI)