Per-Engine Behavior: ChatGPT, Perplexity, Google AI Overviews, Gemini, Claude
Copy-ready Claude prompt
My product category is {{product_category}}. Given that Reddit's citation share is ~46.7% on Perplexity, ~21% on Google AI Overviews, and ~0.1% on Gemini, and that bottom-of-funnel queries see 20.1% Reddit reliance vs 2.5% top-of-funnel, help me rank which 3 engines and which funnel stage deserve my next 30 days of Reddit-engagement effort.Learning objectives
- Quote Reddit's citation share on at least four distinct AI engines.
- Explain why citation share is volatile and name one documented collapse event and its cause.
- Explain funnel-stage dependency: why Reddit matters more at bottom-of-funnel queries.
- Explain domain-overlap data showing why per-engine optimization is required, not optional.
Prerequisites: Lesson 2.3.1.
Core concepts
The single biggest strategic mistake in early GEO practice is treating "AI search" as one channel. It isn't. Citation behavior varies by engine more than SEO ranking factors ever varied by search engine in the 2010s, and a strategy built only on ChatGPT data will misallocate effort against Perplexity, Gemini, and Google AI Overviews.
Start with the spread. Reddit makes up roughly 46.7% of Perplexity's top-10 citations, nearly 3x its next-closest source, YouTube, at 13.9%. In Google AI Overviews, Reddit holds about 21% of citations. In Gemini, by sharp contrast, Reddit is cited in only about 0.1% of responses (Perplexity citation studies; brandonleuangpaseuth; Profound). If your GEO plan allocates effort evenly across engines, you are radically over-investing in Gemini and under-investing in Perplexity relative to where Reddit actually moves the needle. Search Engine Land's coverage of a 30-million-source Peec AI study confirms the general shape across ChatGPT, Google AI Mode, Gemini, and Perplexity/AI Overviews collectively: Reddit #1, then YouTube, LinkedIn, Wikipedia, Forbes, but the per-engine weighting inside that ranking is exactly what differs enough to change your channel mix.
Citation share is also far more volatile than classic SEO rank, and this is a genuinely new risk category you must build into any plan. Semrush tracked ChatGPT citing Reddit in roughly 60% of relevant responses in early August 2025, collapsing to about 10% by mid-September 2025, as OpenAI deliberately reduced over-reliance on any single domain, a shift isolated specifically to ChatGPT, not the other engines. An even sharper example: when Reddit sued Perplexity in October 2025 over unauthorized scraping, Perplexity's Reddit citation share reportedly dropped roughly 86% almost immediately, with YouTube filling the gap (SE Ranking). Litigation, policy changes, and single-vendor algorithm tuning can each erase a large share of your citation visibility overnight, on one engine, with zero warning. The practical lesson: never build a GEO strategy that depends on one engine's current citation behavior remaining stable, and always diversify the content types you're optimizing (thread engagement, YouTube presence, structured on-site content) so a single-engine collapse doesn't zero out your visibility.
A second dimension worth internalizing for prioritization: Reddit's citation reliance is not uniform across the buyer journey. Google AI Overviews cite Reddit on just 2.5% of top-of-funnel queries, rising to 14.3% of mid-funnel queries, and 20.1% of bottom-of-funnel, purchase-intent queries (Profound). Reddit matters most exactly at the moment closest to a buying decision, which is also the moment your competitor's citation, not yours, decides whether a prospect adds you to their shortlist. This should reorder your priority list: engineer citable threads around comparison and "which tool should I buy" queries before broad awareness-stage topics.
Finally, know the overlap data, because it explains why cross-engine optimization can't be done once and forgotten: only about 11% of domains are cited by both ChatGPT and Perplexity, and Google AI Overviews and AI Mode share the same URLs just 13.7% of the time (Leapd / how-AI-chooses-sources studies). Each engine is functionally running its own separate ranking system on top of largely the same underlying web. There is also a live, longer-arc shift to track: some 2026 datasets show YouTube overtaking Reddit as the top social citation source in certain windows (~16% vs Reddit's ~10% over a six-month period), with Ahrefs finding brand mentions in YouTube titles and transcripts as the single strongest correlate of AI Overview visibility. Reddit and YouTube together still cover roughly two-thirds of AI category answers, treat them as a paired channel, not a single one.
Video lessons
Supporting reading
- Top 10 Sources LLMs Cite Most in 2026, Contently (https://contently.com/2026/04/29/top-sources-llms-cite/), a clean, citable leaderboard including US-vs-global differences.
- AI Platform Citation Source Index 2026 Shows Reddit's Surge and a New Era of Volatile AI-Generated Answers, TechEdgeAI (https://techedgeai.com/ai-platform-citation-source-index-2026-shows-reddits-surge-and-a-new-era-of-volatile-ai-generated-answers/), large-sample, recent, cross-engine corroborating evidence.
- ChatGPT Often Retrieves But Rarely Cites Reddit Pages, Data Shows, Search Engine Journal (https://www.searchenginejournal.com/chatgpt-often-retrieves-but-rarely-cites-reddit-pages-data-shows/572243/), accessible write-up of the retrieval-vs-citation gap, reinforcing Lesson 2.3.1 at the per-engine level.
Exercise
Query the same bottom-of-funnel, purchase-intent question ("[competitor A] vs [competitor B] for [use case]") on ChatGPT, Perplexity, and Google AI Overviews. Record which engine cites Reddit, which cites YouTube, and which cites neither.
Assignment
Build a one-page "per-engine citation profile" for your product category: for each of ChatGPT, Perplexity, Google AI Overviews, and Gemini, note Reddit's approximate citation share and one implication for where you'll invest effort first.
Claude workflow
- Skill idea: a per-engine citation-share dashboard input generator, converting the published percentages plus a company's own tracked queries into a prioritized engine/funnel-stage matrix.
- Automation: a scheduled (weekly) multi-engine query test across a fixed set of bottom-of-funnel questions, logging which engine cites Reddit/YouTube/neither, the first building block of the citation-tracking system built in Lesson 2.4.3.
Expected outcomes
- Can quote Reddit's citation share on at least four engines from memory.
- Can name one documented citation-share collapse event and its cause.
- Written per-engine citation profile with a funnel-stage-informed prioritization on file.