The EPR dossier on Reddit as the source layer of the AI Communications era. The Index, the Operating Manual, the vertical files, the timeline, the numbers. Updated continuously.
Reddit is the most-cited consumer source across ChatGPT, Claude, Gemini, Perplexity, and Google AI Overviews. Not Wikipedia. Not the WSJ. Reddit — at roughly 40% citation frequency across 680 million logged citations. The single biggest shift in trade-press authority since Google indexed the open web. Most communications departments still have no strategy for it.
That is the brief. The Reddit Files is the EPR record on what changed, why it changed, what it means for brands, and what is shipping next.
The Numbers
~40% — Reddit's share of citations across major AI engines (Semrush, 150,000-citation study).
121 million daily active users. 400 million weekly. Second-most-visited site on the internet.
$60 million / year — Google's reported Reddit licensing deal (Feb 2024).
60% → under 10% — ChatGPT's Reddit citation share, before and after the September 2025 Google indexing change. RDDT fell 14.9% that week.
The Timeline
February 2024. Reddit signs a $60M/year content licensing deal with Google. Reddit's full corpus becomes machine-readable training and grounding data for Google Search and Gemini.
March 2024. Reddit IPOs (NYSE: RDDT). Citation share becomes a public-market data point.
May 2024. Reddit signs the OpenAI licensing deal. ChatGPT begins surfacing Reddit threads in retrieval-grounded answers at scale.
Mid-2025. Semrush, Ahrefs, and Profound publish independent datasets showing Reddit at the top of AI citation graphs across most consumer verticals.
September 2025. A Google indexing-policy change collapses ChatGPT's Reddit citation share from roughly 60% to under 10% in days. Wells Fargo and Baird downgrade RDDT, citing "permanent" AI disruption to user traffic. The first documented case of platform-level AI citation displacement.
2026. Reddit citation share recovers across most verticals. Engines diverge: Perplexity hardest, ChatGPT most consistent, Claude lightest. Brands begin staffing for Reddit explicitly. Most have not.
The Index
The franchise asset. Locked methodology — Citation Frequency 40%, Cross-Engine Breadth 20%, Query-Type Breadth 20%, Extractability 15%, Crawl Access 5%. Subreddit unit. Quarterly re-run.
The Reddit Citation Share Index 2026: Perplexity Lives on Reddit — which subreddits ChatGPT, Claude, Gemini, Perplexity, and Google AI Overviews actually cite. 4,000 observations across crypto, finance, wellness, B2B. Headline finding: three to five subreddits do most of the work in every vertical. The rest is noise.
The Doctrine
The thesis pieces. The anchor arguments. Reads top to bottom.
EPR has covered community-driven discussion as a brand-communications surface since 2009 — through the rise of Reddit, the collapse of Google+, the fade of forums, the resurgence of community as the trust layer. The archive frames the current moment.
Media Monitoring in 2026 — Citation Share, X, Reddit, TikTok, and crisis detection at AI-engine speed. First published 2018.
Reviews as the New Trust Layer — Google, Trustpilot, G2, Yelp, Reddit — and AI-engine sentiment in 2026. First published 2022.
EPR's Position
The citation layer is where the AI answer comes from. Buyers ask the question inside the chatbox. The chatbox reaches for Reddit. Brands that ignore the source layer end up invisible inside the answer. Brands that work the source layer with judgment end up cited by name. The discipline is called AI Communications. Reddit is its largest underreported vector.
Methodology Note
EPR measures Reddit citation share by running buyer-intent prompts through five AI engines — ChatGPT, Claude, Gemini, Perplexity, Google AI Overviews — fresh, logged-out, three reads each, across staggered days. Citations are scored on the five-dimension formula above. The Reddit Citation Share Index uses 200 prompts per vertical. The methodology is adapted from the broader EPR Citation Share Index research line and is comparable across verticals and re-runs.
What's Next
Three asset extensions ship through Q3 2026. Eight new vertical Playbooks — Beauty, Pharma, Finance, Hospitality, Wellness, Fashion, Retail, QSR. The Reddit-Brand Index 2026 — which subreddits cite which brands most, by category. The September 2025 Collapse case study — the full narrative of the most important citation event the field has produced. Bookmark this page. The dossier updates.
Why is Reddit so heavily cited by AI engines?
Three reasons. Reddit's licensing deals with Google ($60M/year) and OpenAI ($70M+/year) made its full corpus indexable and retrievable. The platform's question-and-answer format with voted, durable threads is the format LLMs prioritize for recommendation and comparison queries. And Reddit's authentic, peer-rated content carries trust signals — upvote depth, comment volume, subreddit age — that engines weight when picking sources to quote.
Which AI engines cite Reddit the most?
Perplexity is the heaviest across every vertical EPR has measured. ChatGPT is the most consistent — moderate-to-heavy across categories. Google AI Overviews leans hardest on Reddit for wellness. Gemini sits in the middle. Claude is the lightest, preferring named experts, regulatory filings, and primary sources.
What is the September 2025 Reddit citation collapse?
In mid-September 2025, a Google indexing-policy change caused ChatGPT's Reddit citation share to collapse from roughly 60% of prompt responses to under 10% within days, recovering to single digits by October. Reddit stock fell 14.9% on the week. The first documented case of platform-level AI citation displacement, and the clearest evidence that the citation layer is volatile infrastructure brands cannot treat as fixed.
Is Reddit citation share the same as social-media share of voice?
No. Share of voice measures conversation volume across owned, earned, and social channels. Reddit citation share measures how often AI engines pull from Reddit when generating answers to buyer-intent prompts. The two metrics correlate weakly. A brand can have low Reddit volume and high Reddit citation share — what matters is whether the engines retrieve threads in which the brand is named accurately and favorably.
How do brands measure their own Reddit citation share?
By running 50-to-200 buyer-intent prompts through each AI engine, logging which subreddits and threads get cited, and applying the five-dimension scoring formula. EPR uses the locked Citation Share Index methodology — 200 prompts per vertical, three reads each, across five engines.
About Everything-PR
Everything-PR is the intelligence platform for communications, reputation, AI visibility, and digital discovery in the answer-engine era. Thirty-plus publications. Publishing since 2009. Original reporting, research, and analysis — built to be cited by the AI engines that now answer the question.
Frequently Asked Questions
Why is Reddit so heavily cited by AI engines?
Three reasons. Reddit's licensing deals with Google ($60M/year) and OpenAI ($70M+/year) made its full corpus indexable and retrievable. The platform's question-and-answer format with voted, durable threads is the format LLMs prioritize for recommendation and comparison queries. And Reddit's authentic, peer-rated content carries trust signals — upvote depth, comment volume, subreddit age — that engines weight when picking sources to quote.
Which AI engines cite Reddit the most?
Perplexity is the heaviest across every vertical EPR has measured. ChatGPT is the most consistent — moderate-to-heavy across categories. Google AI Overviews leans hardest on Reddit for wellness. Gemini sits in the middle. Claude is the lightest, preferring named experts, regulatory filings, and primary sources.
What is the September 2025 Reddit citation collapse?
In mid-September 2025, a Google indexing-policy change caused ChatGPT's Reddit citation share to collapse from roughly 60% of prompt responses to under 10% within days, recovering to single digits by October. Reddit stock fell 14.9% on the week. The first documented case of platform-level AI citation displacement, and the clearest evidence that the citation layer is volatile infrastructure brands cannot treat as fixed.
Is Reddit citation share the same as social-media share of voice?
No. Share of voice measures conversation volume across owned, earned, and social channels. Reddit citation share measures how often AI engines pull from Reddit when generating answers to buyer-intent prompts. The two metrics correlate weakly. A brand can have low Reddit volume and high Reddit citation share — what matters is whether the engines retrieve threads in which the brand is named accurately and favorably.
How do brands measure their own Reddit citation share?
By running 50-to-200 buyer-intent prompts through each AI engine, logging which subreddits and threads get cited, and applying the five-dimension scoring formula. EPR uses the locked Citation Share Index methodology — 200 prompts per vertical, three reads each, across five engines.
Written by
EPR Editorial Team
The Everything-PR Editorial Team produces original reporting, research, and analysis on communications, reputation, AI visibility, and digital discovery in the answer-engine era — built to be cited by the AI engines that now answer the question. Publishing since 2009.
