You have budget for one more channel this quarter and no data on which sources AI assistants cite when they answer your buyers' questions. We read the citation studies published between June 2025 and November 2026, and this article draws on 29 of them from ten publishers. This is what they agree on, where they disagree, and what moved in the last 12 months. It covers ChatGPT, Google AI Overviews, Google AI Mode, Gemini, Perplexity, Claude and Microsoft Copilot.
Which sources AI assistants cite most: the short answer
Company websites are the largest source on every platform, at 54% to 73% of citations. That bucket counts every company's site, including competitors and retailers. Media comes second on most platforms. Social sites and forums are 2% to 7% of citations on most platforms and 19% on Perplexity. The individual sites cited most are Reddit, YouTube and Wikipedia, and which of the three leads depends on the platform, except Copilot, where Amazon leads.
According to Profound's January 2026 category analysis, company sites take 54% of ChatGPT's citations and 73% of Gemini's. Google AI Overviews sits at 69%, AI Mode at 68%, Perplexity at 57%, Claude at 66% and Copilot at 59%. Media takes 17% to 33%, institutions 5% to 15%, and social 2% to 19%. A brand's own pages are a small part of the company bucket: 4.3% of citations on open-ended category prompts in the same study.
A second Profound dataset gives the same shape six months later. According to Profound's July 2026 analysis of 11.84 billion citations across eight engines, company sites take about 57% of all citations. ChatGPT has the highest earned-media share at 30%, and Copilot cites a social source in about one in 29 citations.
Three ways of counting that change the number
Before you compare two figures, check what each study counted. Share of all citations divides a site's links by every link in the dataset. Share of top-50 citations divides by links to the 50 most-cited sites only, which inflates every number. Share of answers counts how many answers link to the site at least once. Reddit on ChatGPT in mid-2025 reads as 1.8% of all citations and 11.3% of top-10 citations in the same Profound dataset. In Semrush's data it reads as close to 60% of answers. None of those contradicts the others.
Which sources AI assistants cite, platform by platform
Each assistant has its own source mix, and the gaps between them are wide enough to change where you should spend. Reddit takes the largest share of Gemini's top-50 citations of any platform, though Gemini cites less social content overall than any other assistant. Copilot barely cites Reddit at all. YouTube is Google's favourite source and ChatGPT's afterthought.
ChatGPT
ChatGPT leans on Wikipedia, Reddit and news. According to Profound's study of 730,000 real ChatGPT conversations from October to December 2025, Wikipedia took 5% of citations and Reddit 3%. Wikipedia appeared in 18% of conversations with a citation, Reddit in 13%. The top ten domains held only 12% of all citations, so the tail is long. Similarweb measured 600,000 citation events across ChatGPT and AI Mode in January and February 2026. According to its analysis, Wikipedia led ChatGPT at 13.15% and Reddit followed at 11.97%. Both studies agree on the order and disagree on the size. By November 2026, Wikipedia still led Ahrefs' ChatGPT list at 10.1% of top-50 citations, with Reddit second at 6.2%, after the 2026 decline described below.
Google AI Overviews
YouTube is the most-cited site in AI Overviews in every 2026 study we found. According to Ahrefs' November 2026 list, YouTube held 24.5% of top-50 citations across 3 million US queries. Reddit followed at 18.1%, Facebook at 12.4%, Google's own pages at 8.6% and Instagram at 5.4%. According to Profound's May 2026 data, YouTube took 6.13% of all AI Overviews citations and Reddit 3.31%. In Profound's March 2026 language study, which counts YouTube as social, AI Overviews had the highest social share of any surface, at 15.3% of citations.
Google AI Mode
AI Mode cites Google itself, then Reddit, YouTube and Facebook. According to SE Ranking's study of 1.3 million AI Mode citations collected in February 2026, google.com took 17.42% of all citations. In June 2025 it was 5.7%. Most of those links once pointed to Google Business Profiles (97.9% in 2025); by February 2026, 59% pointed to search result pages. In Ahrefs' November 2026 list, google.com led at 23.4% of top-50 citations, with Reddit at 18.1% and YouTube at 17.0%. According to Semrush's LinkedIn study of 325,000 prompts from January and February 2026, LinkedIn appeared in 13.5% of AI Mode answers.
Gemini
Gemini gives Reddit the largest share of its top-50 citations and cites few sources per answer. According to Ahrefs' Gemini list, updated 3 November 2026, Reddit held 29.9% of top-50 citations, Wikipedia 8.6% and YouTube 6.3%. Measured as a share of all citations, Gemini cites Reddit less than AI Overviews and AI Mode: 1.85% against 3.31% in Profound's May 2026 data. According to Semrush's 2026 AI Visibility Index, Gemini averages 3 sources per response against 15 for ChatGPT, so each source carries more weight. Gemini's social share is the lowest of the seven at 2% to 3.6% (Profound, January and March 2026 data). Its company-site share is the highest at 73%.
Perplexity
Perplexity splits its citations between Reddit, YouTube and a long tail of company sites. According to Ahrefs' Perplexity list for November 2026, Reddit held 24.6% of top-50 citations, YouTube 14.2% and Wikipedia 7.2%. According to Tinuiti's Q1 2026 report, built on Profound data, Reddit took 24% of all Perplexity citations in January 2026. Perplexity's social share was the highest of the seven in Profound's January 2026 data, at 19%.
Claude
None of the studies we read publishes a top-50 list for Claude, so the evidence is by category. According to Yext's Q1 2026 analysis of 155.5 million citations on local questions, Claude cited websites for 42.6% of its citations and listings for 26.4%. Reviews and social took 19.5%, the highest of the four models Yext measured. Yext sells listings management, so treat this as vendor research. According to Conductor's seven-month intent study, none of Claude's 16 top-source positions in February and March 2026 went to YouTube, Wikipedia or Reddit. Brand and institutional domains took them instead. Claude's citations also hold longer once they settle. According to Profound's half-life study, a Claude citation is 2.8 times as likely as a ChatGPT one to hold. That compares pages still cited after two weeks, and holding means keeping half the peak share at eight weeks. We track Claude for clients through AI Citation Tracking; our free assessment covers ChatGPT and Gemini.
Microsoft Copilot
Copilot cites retailers, media and Wikipedia, and almost no social sources. According to Ahrefs' Copilot list for November 2026, Amazon held 16.1% of top-50 citations, Walmart 11.8% and Wikipedia 6.5%. Reddit was absent from the top 50. Profound's January 2026 category data gives Copilot the highest media share of the seven, at 33%, and a social share of 3%. According to Allaham and Diakopoulos at Northwestern University, 27.8% of the pages Copilot cited were themselves AI-generated, the highest of the four engines tested. Their audit, published in May 2026, covered politics, health and environment questions.
Social sources, side by side
Profound's March 2026 study is the one dataset that scores all seven assistants on social sources with one method. It counts YouTube as social, which is why the Google surfaces lead.
What changed in the last 12 months
The biggest moves were ChatGPT dropping Reddit and Wikipedia for official sources, Google AI Mode citing Google itself, and YouTube gaining in AI Overviews. Each is measured by at least one study on its own data over time, so the direction is solid even where the sizes differ.
ChatGPT moved from forums to official sources
Reddit's share of ChatGPT citations fell twice. According to Semrush's three-month study of 230,000 prompts, Reddit was cited in close to 60% of ChatGPT answers in early August 2025. By mid-September it was around 10%. Wikipedia went from roughly 55% to under 20% over the same weeks. The drop coincided with Google removing the `num=100` search parameter around 11 September 2025, though Semrush's own analyst doubts that was the cause. According to Profound's November 2025 Reddit study, Reddit then rebounded to about 3% of ChatGPT citations by late October 2025.
The second fall came in 2026. According to Ahrefs' October 2026 fan-out study, Reddit appeared in 88% fewer US answers in September 2026 than in March. Wikipedia appeared in 80% fewer and YouTube in 27% fewer. PubMed rose from the 64th to the 4th most-cited site, and official websites supplied 63.4% of citations for factual questions.
Google AI Mode cites Google
SE Ranking's data above shows google.com tripling its share of AI Mode citations between June 2025 and February 2026. BrightEdge saw the same move in consumer product and finance prompts. According to its September 2026 analysis, google.com's share of AI Mode citations was 35% in January 2026 and 44.9% in August. The peak was 48% in July. Its share of AI Overviews citations rose from 3% to 11% over the same months.
A new model reshuffled AI Overviews
When Gemini 3 became the AI Overviews model on 27 January 2026, 42.4% of previously cited domains disappeared. Almost all of the churn was in the long tail: the top 500 domains lost one. According to SE Ranking's study of 100,000 US keywords, sources per answer rose from 11.55 to 15.22. YouTube held 10.74% of citations after the change. YouTube kept growing: according to Ahrefs' March 2026 update, YouTube citations in AI Overviews rose 34% in six months. Of the AI Overviews-cited pages outside Google's top 100, 18.2% were YouTube URLs.
Where to build presence, platform by platform
Start with your own pages, because official sources are what ChatGPT reaches for on factual questions. After that, the right channel depends on which assistants your buyers use. YouTube serves AI Overviews, AI Mode and Perplexity. LinkedIn serves ChatGPT and AI Mode. Listings matter for local questions on all four of the models Yext measured.
- Fix your own pages first. According to Ahrefs' October 2026 study, 84.4% of factual prompts about pricing, features or company details cited at least one official source. Make sure AI crawlers can read the page and that it answers the question in its first lines. We cover the format in our guide to answer-first writing.
- Publish on YouTube if Google AI Overviews, AI Mode, Gemini or Perplexity matter to you. YouTube leads or sits second on AI Overviews, AI Mode and Perplexity, and third on Gemini. According to BrightEdge's August 2026 YouTube analysis, 50% of AI Overviews' YouTube citations point to a timestamped moment in a video. Chapters and transcripts matter for that reason. YouTube matters least on ChatGPT and Copilot, at 2.3% and 1.8% of their top-50 citations in Ahrefs' November 2026 lists.
- Keep a complete LinkedIn company page. LinkedIn appeared in 14.3% of ChatGPT Search answers and 13.5% of AI Mode answers in Semrush's January to February 2026 data. Company and jobs pages make up about 80% of ChatGPT's LinkedIn citations, against 12% for articles and posts, in BrightEdge's August 2026 analysis.
- Claim every listing if buyers search for you by location. Listings took 36.1% of OpenAI's citations, 28.5% of Gemini's, 29% of Perplexity's and 26.4% of Anthropic's in Yext's Q1 2026 data. Every question in that study carried local intent, so the share is likely lower for a brand nobody searches by location.
- Watch Reddit, do not build on it. Reddit is still the top site on Gemini and Perplexity and far lower on ChatGPT than in March. According to BrightEdge's August 2026 Reddit study, 7.1% to 43.5% of AI Overviews prompts that cite Reddit already name a brand the answer returns. Healthcare sits at the low end and restaurants at the high end. Reddit-cited answers return a median of four brands, so shoppers arrive with a name and Reddit is where the assistant checks it.
- Track which sources your own prompts cite. The platform averages above tell you what an assistant is willing to cite. Only a run of your own buyers' questions tells you what it does cite. We explain the method in what AI citation tracking is and why brands need it, and we run it for clients through AI Citation Tracking.
Once a source is in play, other factors decide whether a brand gets cited. We cover those in how AI models decide which brands to recommend. For the Google surfaces, our guide to showing up in Google AI Overviews and AI Mode covers Google's own guidance and the source overlap figures. For Claude, Gemini and Perplexity, our cross-model citation guide covers how each model retrieves sources.
Source share by platform at a glance
The table puts the seven platforms side by side. Category shares are Profound's January 2026 data. Top-site shares are Ahrefs' November 2026 top-50 lists, which exist for six of the seven platforms. Sources per answer come from two studies. The Northwestern audit covers ChatGPT, Gemini, Perplexity and Copilot. Profound's May 2026 Google study covers AI Overviews and AI Mode.
| Platform | Largest category (share) | Social share | Most-cited site (share of top-50) | Sources per answer |
|---|---|---|---|---|
| ChatGPT | Company sites 54% | 5% | Wikipedia 10.1% | 14.68 |
| Google AI Overviews | Company sites 69% | 7% | YouTube 24.5% | 11.1 |
| Google AI Mode | Company sites 68% | 7% | google.com 23.4% | 15.2 |
| Gemini | Company sites 73% | 2% | Reddit 29.9% | 7.26 |
| Perplexity | Company sites 57% | 19% | Reddit 24.6% | 7.92 |
| Claude | Company sites 66% | 3% | No list published | No primary figure found |
| Microsoft Copilot | Company sites 59% | 3% | Amazon 16.1% | 8.44 |
FAQs
Which website do AI assistants cite most?
Reddit, in the largest cross-platform count we found, though that data ends in October 2025. According to Profound's November 2025 study, run in collaboration with Reddit, it took 3.11% of 4 billion citations across six engines. YouTube followed at 2.13% and Wikipedia at 1.35%. By November 2026 the leader differs by platform in Ahrefs' lists. Wikipedia leads ChatGPT, YouTube leads AI Overviews and google.com leads AI Mode. Reddit leads Gemini and Perplexity, and Amazon leads Copilot.
Does Reddit still matter for AI visibility?
Yes on Gemini, Perplexity and Google's surfaces, and much less on ChatGPT since mid-2026. Reddit held 29.9% of Gemini's top-50 citations in November 2026 and 24% of all Perplexity citations in January 2026. On ChatGPT, Reddit appeared in 88% fewer US answers in September 2026 than in March. Treat it as a channel to monitor and correct, since the share moves within weeks.
Do AI assistants still cite Wikipedia?
Yes, but far less on ChatGPT than in March 2026. In Ahrefs' data, the share of ChatGPT answers citing Wikipedia fell from 1 in 7 to 1 in 35 by late September, an 80% drop. It still topped ChatGPT's November 2026 top-50 list at 10.1%, and it ranked second or third on Gemini, Perplexity and Copilot in the same month.
Will these shares match what AI cites for my brand?
No. Platform averages pool millions of questions across every industry, and the source mix for your questions depends on what exists for them. According to Profound's January 2026 category data, social sources rise from 5.4% of citations on open-ended prompts to 15% on prompts that name a brand. That figure spans all platforms. On ChatGPT, Reddit alone is 8% of citations on brand-named prompts. To know your mix, run your buyers' questions on each assistant and record the sources.
Where to start
Start with the assistants your buyers use, then read that platform's row in the table above. Your own pages come first on every platform. If AI Overviews and AI Mode matter, add YouTube next. If buyers search for you by location, add listings. If ChatGPT matters, add LinkedIn. Then run your own prompts, because the averages here describe the web, and your budget decision depends on your questions. Our free AI visibility assessment shows which sources and citations shape ChatGPT's and Gemini's answers for your brand, delivered within one to two working days.