The Sources of Generative AI: Where ChatGPT, Perplexity, and Gemini Get Their Answers

The categories of sources cited by the assistants, their relative importance based on the type of question, the 2025–2026 studies, and what an SME can do to be included in each one

Key Takeaways

  • The finding: Assistants cite pages from search indexes, with a preference for media outlets, Wikipedia, online communities (Reddit, forums), review platforms, and comparison sites; brand websites are cited to provide information about the brands themselves, rather than as recommendations.
  • Depending on the question: "Understand" cites media outlets and expert websites; "Compare" and "Choose" cite comparisons, reviews, and online communities; "Local" cites Google listings and directories.
  • For an SME: Be present in at least three categories (website, reviews, a relevant third-party platform) and maintain consistency across all of them.
  • The Overlooked Lever: communities and independent comparisons, which AI systems interpret as user reviews.

When an AI assistant responds, it draws on pages it has found in an index and just read. Knowing which types of sources it prioritizes helps you decide where to focus your efforts. Studies from 2025–2026 (Semrush, Ahrefs, Profound, BrightEdge, and agency analyses) point to common trends, with variations depending on the search engine and the type of query. This article summarizes these sources, explains their relative importance, and outlines, for each one, what an SME can do. The search mechanism is described in Understanding AI Engines.

Source families and their weights

FamilyExamplesObserved weightFor which questions
Brand and Publisher WebsitesProduct pages, “About Us” pages, company guidesHigh for describing a brand, medium for recommending"What does X do?", "How much does X cost?"
Media and Trade PressNewspapers, business and industry news websitesHigh, especially Perplexity and AI insightsUnderstanding, News, Statistics
Wikipedia and encyclopediasWikipedia, WikidataVery high for definitions and entities"What is…", "Who is…"
CommunitiesReddit, forums, Quora, groupsStrong and growing, especially ChatGPT and Perplexity; Google has a deal with RedditCompare, choose, user reviews
Reviews and RatingsGoogle, Trustpilot, G2, Capterra, Verified ReviewsRaised to Give Recommendations"Which tool / service provider…," "Is X reliable?"
Comparisons and Lists"Top 10…" lists from media outlets, expert blogs, and review sitesVery high for brand recommendationsChoose
VideoYouTube (transcripts), TikTok to a lesser extentStrong on Google and Gemini, weak elsewhereHow-to, Tutorials
Directories and Index CardsGoogle Business Profile, Yellow Pages, business directories, LinkedInFocused on the Local and Corporate Identity"Near Me," "Who Is..."
Academic and Institutional SourcesStudies, public reports, official websitesRaised on Facts and FiguresVerify, calculate

Order of magnitude of the 2025–2026 studies: brand pages account for 20–30% of citations, media outlets 15–25%, Wikipedia 5 to 15%, Reddit and online communities 5 to 15% (more so for choice-related topics), and review and comparison sites 10 to 20%. These percentages vary significantly depending on the search engine and industry.

Differences Between Engines

  • ChatGPT It cites a variety of sources, with a strong emphasis on the media, Wikipedia, and online communities for recommendations; it uses the Bing index.
  • Perplexity He cites many sources (5 to 10), prioritizes recency, and highlights expert media outlets and websites; he enjoys reading Reddit and watching YouTube.
  • Gemini and AI Previews draw from Google’s index: there is a strong correlation with the top 10; Reddit, YouTube, and forums have been overrepresented since the 2023–2024 updates, which favored “experiential” content.
  • Co-pilot Next is Bing, with a focus on Microsoft and LinkedIn sources.

What an SME Can Do, One Family at a Time

FamilyActionEffort
Brand WebsiteA comprehensive "About Us" page, factual product pages, structured guides; see Optimize your "About Us" pageMedium, once
MediaLocal and industry-specific media relations, opinion pieces, and original data that journalists use in their reportingContinuous
Wikipedia and WikidataCreate the Wikidata entry (accessible to any company); create a Wikipedia entry only if the notability criteria are met; otherwise, do not create oneWeak for Wikidata
CommunitiesParticipate honestly in discussions within your industry (Reddit, forums, LinkedIn), answer questions without self-promotion; encourage customers to share their experiencesContinuous, moderate
ReviewsCollect reviews on Google and on the industry's leading review platforms (G2, Capterra, Trustpilot), and respond to all of them; see collect high-quality reviewsContinuous
ComparisonsBe featured in independent industry comparisons; publish its own unbiased comparisons, which are citedMedium
VideoPublish on YouTube with a transcript and chapters; see Index a podcast or video in AI systemsMedium
Directories and Index CardsComplete Google listing, up-to-date LinkedIn profile, consistent business directoriesLow

The Influence of Communities and Opinions

The most noticeable change since 2024 is the prominence of Reddit, forums, and review platforms in recommendation responses. Assistants treat these as the voice of users, which is less suspicious than a brand page. For a French small business, Reddit remains secondary; the equivalents are industry forums, LinkedIn and Facebook groups, review sites, and customer communities. Two rules: never fabricate reviews or discussions (platforms and AI detect this, and the penalty is long-lasting), and encourage real customers to share their opinions where AI reads them. Monitoring these mentions is described in monitor its presence in generative AI.

Measure

For your key questions, note the sources cited in each monthly report and categorize them by type: you’ll see where your competitors are present and you are not. An SME that is absent from reviews and comparisons while its competitors are featured knows what its priority is. The indicators are in GEO's KPIs.

Tip: Ask ChatGPT and Perplexity the question, “Which [your profession] should [your target audience] choose?” and list the ten sources cited by category. If none of them are brand websites, don’t focus on your own website first: instead, work on your presence in the comparison sites, reviews, and communities mentioned in the response.

How GreenRed Can Help You

Instead of juggling multiple tools, GreenRed's GEO tracking brings these metrics together in a single dashboard, compares them over time, and shows you the top priorities. You can try it for free—no credit card required—on the page Rates.

Frequently Asked Questions

Which sources does ChatGPT cite most often?

Pages from the Bing index, with a strong emphasis on media sources, Wikipedia, and brand websites for descriptions, and communities (Reddit, forums) and review platforms for recommendations. The breakdown varies depending on the question: “understand” cites media outlets and experts, while “choose” cites comparisons and reviews.

Do you have to be on Reddit to be cited by AI?

For a French small or medium-sized business, Reddit is of secondary importance; the equivalents are industry forums, LinkedIn and Facebook groups, and review sites—which AI systems also scan. Participate honestly in discussions within your industry and encourage your customers to share their experiences. Never fabricate discussions or reviews.

Is Wikipedia indispensable?

Not for an SME: Wikipedia’s eligibility criteria are strict, and a page created without sufficient notability will be deleted. Instead, create a Wikidata entry (identity, website, social media), which is available to any business and helps search engines recognize the entity.

How can I find out which sources are cited in my questions?

Ask your targeted questions to ChatGPT, Perplexity, and Google (AI preview), and note the sources cited, or use a GEO tracking tool that automatically lists them. Categorize them by type (brand, media, reviews, community, comparisons) to see where your competitors are active and where you’re missing out.

Track your visibility on AI platforms

GreenRed monitors whether and how ChatGPT, Perplexity, and Gemini mention your brand and your competitors.

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