What AI Assistants Cite When Shoppers Ask What to Buy: Early Data from 1,300 Answers
When a shopper asks ChatGPT, Perplexity, Gemini or Google AI Overview “what's the best portable monitor stand?”, the answer comes with sources: the web pages the assistant read before replying. Those sources decide which brands get recommended. If you sell on Shopify and want AI search to mention your store, it helps to know where the assistants are reading.
We build AEO Tracker, a Shopify app that asks AI assistants real buying questions every week, with live web search turned on, and saves every answer along with its sources. This post shares what those sources look like so far.
The short version:
- Reddit is the most-cited site. It turns up in about half of all answers, in almost every product category we track.
- Brands' own websites are read constantly. More than half of answers cite at least one brand's own site.
- “Best X” round-ups are the most-cited kind of page.
- Each assistant has its own habits. Perplexity reads forums in 85% of answers, ChatGPT in 17%. Gemini cites YouTube in half its answers, ChatGPT almost never.
- The sources are fairly stable. From one week to the next, assistants go back to many of the same sites, so they are a real target, not a lottery.
How we measured this
We looked at about 1,300 answers to real shopping questions, collected between July and early October 2026 across seven product categories: coffee (two kinds), desk accessories, snowboards, headphones, collectibles and bike accessories. Every answer came from a check with live web search on, so the sources are pages the assistant actually read for that answer, not something remembered from training.
Some honest limits before the numbers:
- This is early data. Many of the answers come from our own test stores and the first stores to install AEO Tracker. Coffee questions make up about 60% of the answers, so we checked each finding category by category and only lead with the ones that hold across most categories.
- We count answers, not links. Assistants report sources differently. Perplexity and Gemini list everything they read; ChatGPT lists only what it quotes. So a raw link count would make Perplexity look like it reads far more. Instead, every percentage below is the share of answers that cite at least one site of a given kind.
- Claude and Grok are left out. We check both, but had too few of their answers to say anything reliable yet.
Which websites do AI assistants cite most?
Reddit, by a distance. It appeared in 613 of the 1,284 answers that cited anything, in six of our seven product categories, and on every assistant we had enough data for.
YouTube came next, appearing in 290 answers and in all seven categories. After that, the sites cited across many different product categories were familiar names: Facebook, Amazon, Forbes, Trustpilot, The New York Times, Instagram, Consumer Reports and the Shop app.
But the general-purpose giants are only part of the picture. Every category also had its own niche sites that showed up again and again: a caffeine database for coffee questions, specialist review sites for headphones, snowboard magazines and shops for snowboards. If you want to know what the assistants read for your products, the niche sites matter as much as Reddit does.
Do AI assistants read brand websites?
Yes, constantly. More than half of answers (55%) cited at least one brand's own website, such as the maker of a product the answer went on to recommend. That held in all seven categories.
That is a floor, not a ceiling: we only count a site as a brand's site when we can match it confidently, so many smaller shops' sites fall into “other” and aren't counted.
ChatGPT in particular likes product pages. Of the pages it cited, 27% were product pages, against 7% for Perplexity and 8% for Google AI Overview.
What kind of page gets cited?
Sorting cited pages by what they are, the clear winner is the “best X” round-up (“The 10 Best Portable Monitor Stands”, “Top 7 High-Caffeine Coffees”). These made up 31% of all cited pages with a readable title, ahead of product pages (10%) and forum threads (9%).
Many of these round-ups are kept fresh: one in five pages Perplexity cited had a year in its title.
Do different AI assistants cite different sources?
Very much so. The same question can be answered from quite different corners of the web depending on who you ask:
| Share of answers citing at least one... | Perplexity | Gemini | ChatGPT | Google AI Overview |
|---|---|---|---|---|
| Forum (Reddit, Quora) | 85% | 47% | 17% | 41% |
| Video (YouTube) | 11% | 50% | 1% | 38% |
| Marketplace (Amazon, Etsy, the Shop app) | 41% | 15% | 6% | 14% |
| Press (Forbes, The New York Times, Tom's Guide) | 22% | 10% | 7% | 6% |
| Brand website | 62% | 62% | 60% | 34% |
Part of ChatGPT's lower numbers comes from it listing only the sources it quotes, so compare down a column more than across a row. Even so, the pattern is strong: Perplexity leans on forums and marketplaces, Gemini and Google AI Overview lean on YouTube, and ChatGPT leans on brand sites and product pages.
How often do AI sources change?
Less than you might fear. When we asked the same question again on the next check, usually a week later:
- Perplexity cited 74% of the same sites again.
- Gemini cited 43% of them again.
- ChatGPT and Google AI Overview each cited about a third again.
So the sites an assistant reads for your questions are a fairly stable target, especially on Perplexity. But a good share changes every week, which is why a single check is a snapshot rather than the full story.
An early signal we're still testing
On our own store, Flexsta (the company behind AEO Tracker), and one other store, there's a striking pattern. On general questions that didn't mention the store by name, when the assistant cited the store's own website it named the store 93% of the time. When it didn't cite the store's site, it named the store 10% of the time.
We are not drawing conclusions from this yet. It's two stores, and the cause could run either way: the site being read may lead to the mention, or an assistant that has already decided to recommend a store may simply link to it. We'll report back when we have more stores.
Two things that made no difference
Not everything people worry about shows up in the data:
- Review stars in your page code. Across 232 Shopify stores, stores that publish review ratings in their structured data (the hidden product details search engines read) were cited about as often as stores that don't: 23% against 18%, a gap small enough to be chance.
- Blocking AI crawlers by accident. Of 233 Shopify stores we checked, none blocked the crawlers AI search tools use to find pages to cite. The “block AI bots” snippets that circulate block the bots that collect training data, not the ones that fetch pages for answers.
What we'd do with this
If we were a Shopify store wanting AI assistants to recommend us, based on what the data shows so far:
- Find the round-ups. Search for “best [your product]” and see which list articles come up. Getting into those is one of the most direct routes into an AI answer.
- Take part in Reddit honestly. Answer questions in the communities where your customers ask for recommendations. Spam gets removed and remembered; genuinely useful answers get read.
- Make your product pages answer buying questions. Brand sites and product pages are read constantly, especially by ChatGPT. Say clearly who the product is for and how it compares, in plain words.
- Consider video. If Gemini or Google AI Overview matter to your customers, YouTube reviews and demos are one of their favourite sources.
- Check which sites the assistants read for your own questions. The averages above hide a lot: each product category has its own handful of sites that matter most.
Frequently asked questions
What websites do AI assistants cite most for product recommendations?
In our data, Reddit is cited most, appearing in about half of answers that cite anything. YouTube, brand websites, marketplaces like Amazon, and press sites like Forbes and The New York Times follow. Each product category also has its own specialist sites.
Does ChatGPT cite Reddit?
Sometimes, but far less than other assistants. ChatGPT cited a forum in 17% of its answers, against 85% for Perplexity. ChatGPT cited brand websites and product pages more.
Do I need review star markup to be cited by AI?
Our data doesn't suggest it. Across 232 Shopify stores, publishing review ratings in structured data made no meaningful difference to whether a store was cited.
How often do the sources AI assistants use change?
From one weekly check to the next, assistants cited between about a third (ChatGPT, Google AI Overview) and three quarters (Perplexity) of the same sites again.
How can I see which sites AI assistants cite for my store?
AEO Tracker saves the sources behind every answer it checks for your buying questions, and its weekly email lists the sites cited most for your questions that week. The free plan checks five questions a week on ChatGPT.