ChatGPT vs Gemini vs Perplexity: Which AI Platform Matters Most for Your Brand?
How ChatGPT, Google AI Overviews, Perplexity, Gemini and Claude retrieve and cite sources, and why the BVS score is weighted by platform.
Also available in：繁體中文
The AI platform that matters most for a brand is ChatGPT, followed by Google AI Overviews: the first has more than 800 million weekly active users, the second more than 2 billion monthly users. All 5 major AI platforms cite their sources in live-search mode; they differ in how they retrieve web pages and in which settings let your pages be found. That is why the BVS score is weighted by platform.
How do the 5 AI platforms retrieve and cite sources?
The table summarizes what each platform's official documentation says about live retrieval and source citation, along with its BVS weight:
| Platform | Live retrieval | Source citation | Key to being found | BVS weight |
|---|---|---|---|---|
| ChatGPT | ChatGPT search crawls with OAI-SearchBot | Cites source pages in the answer | Allow OAI-SearchBot in robots.txt | 30% |
| Google AI Overviews | Uses the Google Search index | Shows supporting links | Indexed and eligible for a snippet | 25% |
| Perplexity | Native AI search; searches before every answer | Sources on every answer | Allow PerplexityBot | 20% |
| Gemini | Grounding with Google Search | Cites verifiable sources | Same as the Google Search index | 15% |
| Claude | Web search tool | Citations always on when searching | Allow Claude-SearchBot | 10% |
ChatGPT — 30% weight
ChatGPT has the most users of any AI platform. OpenAI announced at DevDay in October 2025 that ChatGPT has more than 800 million weekly active users.
ChatGPT search fetches pages with OAI-SearchBot. OpenAI's crawler documentation says OAI-SearchBot is used to surface websites in ChatGPT's search features, and that it is a separate setting from GPTBot, which is used for training: you can allow OAI-SearchBot to appear in search results while disallowing GPTBot.
Impact on your brand: make sure robots.txt does not block OAI-SearchBot. Otherwise ChatGPT search cannot cite your pages and your BVS D5 stays at 0.
Google AI Overviews — 25% weight
AI Overviews is the generative summary at the top of Google Search. Alphabet said on its Q2 2025 earnings call that AI Overviews has more than 2 billion monthly users in over 200 countries and territories and 40 languages.
Google Search Central explains that there are no additional requirements to appear in AI Overviews and that SEO best practices still apply; a page must be indexed and eligible to be shown with a snippet to appear as a supporting link.
Impact on your brand: traditional SEO is the groundwork. A page that is not in Google's index cannot be a source in AI Overviews.
Perplexity — 20% weight
Perplexity is a native AI search engine that lists sources in every answer. Perplexity's API documentation describes its answers as web-grounded with built-in citations.
Impact on your brand: Perplexity searches before every answer, so page updates show up in its answers relatively quickly. Keep your core pages' information and "last updated" date current.
Gemini — 15% weight
The Gemini API documentation explains that Grounding with Google Search connects Gemini to real-time web content, giving more accurate answers that cite verifiable sources. llmion turns this feature on when monitoring Gemini.
Impact on your brand: Gemini's retrieval is built on Google Search, so what works for Google AI Overviews also helps with Gemini.
Claude — 10% weight
Claude's web search tool documentation states that citations are always enabled for web search, and each citation includes the source URL and title. llmion turns on the web search tool when monitoring Claude.
Impact on your brand: allow Claude-SearchBot and ClaudeBot to crawl your site so Claude can find your pages when it searches.
Why is BVS weighted by platform?
Platforms differ in user base and in their effect on traffic. ChatGPT carries 30% because it has the most users; Google AI Overviews carries 25% because it sits at the top of Google search results; Perplexity carries 20%, reflecting the importance of native AI search; Gemini carries 15% and Claude 10%.
When Google AI Overviews is not monitored, its 25% is redistributed proportionally to the other 4 platforms. The weights are llmion's methodology, based on market influence; see the BVS methodology for details.
Practical steps for each platform
- Open up to crawlers: allow OAI-SearchBot, PerplexityBot, Claude-SearchBot and Google-Extended in robots.txt
- Look after your Google index: both AI Overviews and Gemini are built on Google Search
- Put a direct answer at the top: so any AI that retrieves your page can quote the first 2–3 sentences
- Add numbers and sources: the GEO study (KDD 2024) found that adding statistics, quotations and citations raised content visibility in generative engine answers by 30–40% relative to the original
- Check BVS by platform: wherever D5 is 0, check that platform's crawler settings first
Frequently Asked Questions
Q: Which AI platform matters most for a brand?
By user base, ChatGPT matters most, followed by Google AI Overviews, which is why BVS gives them 30% and 25% of the weight.
The platform your customers actually use may vary by industry and region. The per-platform breakdown in BVS shows your score on each platform so you can decide which to optimize first.
Q: Should I optimize for a single platform?
We don't recommend it. All 5 platforms cite web pages when they search live, so crawlable pages that answer the question directly, with numbers and sources, work everywhere.
Tuning for one platform makes it easy to overlook the crawler settings of the others. BVS is weighted across platforms, so progress on one platform has a limited effect on the total.
Q: Does blocking GPTBot in robots.txt affect ChatGPT search?
Not directly. OpenAI says GPTBot and OAI-SearchBot are independent settings.
GPTBot is for training data and OAI-SearchBot is for ChatGPT search. You can block GPTBot while allowing OAI-SearchBot and still appear in ChatGPT search answers.
Q: Does Google AI Overviews need special optimization?
Google says there are no additional technical requirements or special optimizations; SEO best practices still apply.
A page must be indexed and eligible to be shown with a snippet to become a supporting link in AI Overviews. In practice, a direct answer at the top and specific numbers make a page easier to quote in a summary.
Q: How quickly do platforms cite new content?
Platforms that search live can cite a page once it has been crawled and indexed, usually within days to weeks.
Answers from training data alone only reflect new content after a model update. llmion always prefers live-search mode for monitoring and labels every answer as search mode or memory mode.
Q: Why does Claude have only a 10% weight?
Platform weights are llmion's methodology, set by each platform's influence on brand exposure, and Claude ranks after ChatGPT, Google AI Overviews, Perplexity and Gemini.
The weights reflect exposure, not answer quality. If your B2B or professional-services customers use Claude often, watch the Claude score in the per-platform breakdown.
Q: How is Perplexity different from ChatGPT search?
Perplexity is a native AI search engine that searches and cites sources for every answer; ChatGPT turns on search when it needs to.
For a brand, both require pages that their crawlers can reach. BVS uses D5 source link on both to check whether your website is cited.
Q: How does BVS decide whether the AI cited my website?
BVS D5 compares every source URL listed in the AI answer; if any domain is your website or one of its subdomains, D5 scores 100.
The comparison ignores the www prefix and includes subdomains. Redirect links returned by Gemini are compared using the original domain to avoid false results.
Start monitoring your brand's AI visibility
Free sign-up, 5-minute setup, an automatic BVS report every week
Start free