> ## Documentation Index
> Fetch the complete documentation index at: https://docs.peec.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# ChatGPT site-operator fan-outs — 84% branded, Reddit tops the rest

> David Konitzny's GPT-5.6 analysis (Jul 2026) — the site: operator appears in ~43% of fan-outs (vs 0.004% in GPT-5.5); 84% target brand domains, and Reddit is 71% of non-branded site-operator domains.

ChatGPT 5.6 uses the `site:` operator as a core retrieval tool. David Konitzny's analysis of GPT-5.6 (Luna) fan-outs ([full article](https://www.linkedin.com/pulse/understanding-site-operator-usage-chatgpt-56-fan-outs-david-konitzny-sycce/), Jul 2026) found it in roughly **43% of query fan-outs**, versus 0.004% in ChatGPT 5.5.

How it is used (Jul 2026 data):

* **Mostly one domain per fan-out** — only 9% of cases carry two or three site: commands. The operator narrows the information space to a trusted source.
* **84% of targeted domains are branded** — the model goes straight to the domain offering the relevant product or service. Only 16% are non-branded secondary sources.
* **Reddit is 71% of all non-branded site-operator domains** (93% of the Social & Forums category); **Trustpilot is 54% of the Review & Comparison category**. arXiv appears among public institutions at \~9% of that category.
* **Root domains beat URL paths.** Root-domain targeting pairs with broad informational terms (review, official, service, comparison); specific URL paths pair with product-specific and pricing queries. Product attributes (size, model names, colors) are the most common accompanying terms at 12%.

The pattern: root domains identify trusted sources; URL paths fire when the model already has a precise information need. Persistence of those domains and URLs over time: [ChatGPT fan-out domains vs URLs](/research/chatgpt-fanout-domains-vs-urls). The broader GPT-5.6 shift: [GPT-5.6 retrieval changes](/research/gpt-56-retrieval-changes).

**Source:** [Understanding site operator usage in ChatGPT 5.6 fan-outs](https://www.linkedin.com/pulse/understanding-site-operator-usage-chatgpt-56-fan-outs-david-konitzny-sycce/), David Konitzny, LinkedIn, Jul 2026.