Similarweb today published its 2026 Generative AI Landscape report, documenting a market where ChatGPT's share of standalone web visits has fallen sharply since mid-2024 while advertising has moved from experiment to fixture, appearing in 26% of US desktop ChatGPT chats during June 2026.

The 38-page report, authored by Laurie Naspe and Sam Sheridan of Similarweb's Market Insights team, draws on the company's web, app and advertising intelligence panels. Its central claim is not that generative AI has replaced search. It is that generative AI has become large enough, and fragmented enough, that measuring brand presence across a single platform no longer describes the discovery landscape.

Average monthly web visits to generative AI platforms reached 9.5 billion between June 2025 and May 2026, according to Similarweb, up 70% from 5.6 billion in the preceding twelve months. Monthly unique visitors climbed 57% to 655 million from 418 million. App downloads present a discrepancy worth noting: the report's summary page cites 2.7 billion downloads, up 134% year over year, while the detailed chart on page six shows 4.4 billion downloads against 2.8 billion the prior year, an increase of 58%. The report does not reconcile the two figures.

Fragmentation inside the chatbot market

The clearest structural finding concerns competitive position. ChatGPT remains the largest standalone generative AI website by monthly visits, but its share of the category has eroded steadily. Similarweb's chart of gen AI chatbot websites by visits shows ChatGPT holding above 80% of the tracked set through late 2024, then declining across 2025 and into 2026 to just above 50% by May 2026. Gemini, Claude, Perplexity and DeepSeek absorbed the difference.

That trajectory aligns with figures PPC Land reported in June 2026, when Similarweb data showed ChatGPT at 52.7% and Claude tripling its share. The report frames the shift as fragmentation within web-based usage rather than across the whole AI market, since embedded experiences such as Meta AI and Google AI Mode sit outside the chatbot domain measurements entirely.

The app picture differs from the web picture. Measured by US monthly active users between June 2025 and May 2026, ChatGPT grew 87%, Gemini 31%, Meta AI 435%, Grok 117%, Perplexity 94% and Claude 349%. Two products moved backwards: Microsoft 365 Copilot fell 31% and DeepSeek fell 23%. Growth on the app side did not redistribute share the way it did on the web.

Audience overlap complicates any winner-takes-all reading. Similarweb measured 494 million ChatGPT users worldwide between March and May 2026, of whom 461 million, or 95%, also used Google. Gemini reached 310 million and Claude 86 million over the same window, with 29 million users appearing across all three. The overlap figure held steady at 95% from September 2025.

AI Overviews at 43% of searches, with a caveat

Similarweb's tracking of AI Overviews as a percentage of US searches shows the metric moving from roughly 15% in January 2025 to above 40% by May 2026. The line is volatile rather than steadily rising: it peaked near 40% in August 2025, fell to about 27% in October 2025, recovered through the winter and reached its highest recorded point in May 2026. AI Mode visits climbed in parallel, from roughly 120 million in June 2025 to a peak near 320 million in March 2026, before easing slightly.

That 43% figure sits well above other published measurements. Adthena's June 2026 Monthly AI Data Pulse, covered by PPC Land in July, recorded AI Overviews in 23% of UK searches and 18% of US searches. The gap between the two datasets is substantial and neither company has published a reconciliation. Methodology differences in query sampling, device mix and what counts as an AI Overview appearance plausibly explain much of it, but the divergence is a reminder that no industry-standard measurement of AI Overview frequency currently exists.

What is less disputed is the direction of travel inside Google's own products. AI Mode passed one billion monthly users in May 2026, with query volumes more than doubling every quarter since the US launch.

Prompting habits are leaking into Google

One of the more granular findings concerns query length. Average Google search length in the US rose from roughly 3.33 words in mid-2024 to about 3.51 words by May 2026, with the inflection visible around the AI Mode launch. The distribution shifted at both ends: one-word searches fell from 16.3% to 15.3% and two-word searches from 27.2% to 26.0%, while searches over five words rose from 13.6% to 16.1%.

The shift is small in absolute terms, but longer queries carry different match-type behaviour and different commercial intent than the short keyword strings that defined search advertising for two decades.

Platforms are specialising, and so are their audiences

Similarweb plotted median prompt length against prompts per session for six platforms across June 2025 to May 2026. Claude sits at the far end of both axes, with the longest prompts and the most turns per session. ChatGPT sits nearby. Gemini, Copilot and AI Mode cluster in the shorter, fewer-turn quadrant the report labels quick answers and tasks. Perplexity occupies a middle position it describes as research-oriented.

Audience composition diverges just as sharply. Indexed against Google Search visitors at a baseline of 100, ChatGPT users over-index on restaurants and delivery at 2.4 times, health at 2.3 times and fashion at 2.1 times. Claude users over-index on universities and colleges at 25 times, programming and business services at 3.0 times each. Gemini users over-index on graphics and web design at 4.8 times and computer security at 3.1 times.

For media planners, that spread carries an obvious implication for where a given brand's audience is likely to be asking questions, though the affinity data covers October 2024 to September 2025 and is therefore the oldest dataset in the report.

Age spread and a countercurrent

Chatbot usage has flattened across age brackets. In May 2024, the 18-24 and 25-34 groups accounted for 28% and 33% of US chatbot usage. By May 2026 those figures were 22% and 28%, while the 45-54 bracket rose from 12% to 16% and the 55-plus bracket from 12% to 18%. Half of users are now aged 18 to 34 and half are 35 or older.

Michael Horrocks, Head of Organic and Website at Miro, is quoted in the report saying that growth concentrated in younger demographics can fade with trends, while growth spreading into older generations is often what durable, mainstream adoption looks like.

Running against that adoption curve, Similarweb documents an anti-AI countercurrent among younger users. DuckDuckGo's no-AI search interface at noai.duckduckgo.com draws 33% of its US usage from the 18-24 bracket between March and May 2026, against 16% of total US internet usage from that age group. The report also cites recent US graduation ceremonies where speakers focused on AI drew audible backlash from graduates.

That finding aligns with sentiment research the industry has tracked separately. IAB research published in January 2026 found 82% of advertising executives believed Gen Z and Millennial consumers felt positively about AI-generated ads, against 45% of those consumers who actually did.

Citations, referrals and the folder-depth problem

The share of ChatGPT answers containing web citations rose from roughly 1.3% in June 2025 to 6.8% in May 2026, an increase Similarweb characterises as more than fivefold. Citation rates vary widely by industry: travel at 22.6%, retail at 13.5%, sports at 10.7%, finance at 8.0%, technology at 6.6%, health at 6.3%, media and entertainment at 6.0% and education at 4.8%.

The composition of cited sources varies more than the rate. Across the top 10,000 US desktop citations in May 2026, reviews and user-generated content accounted for 28.9% of ChatGPT citations and news and publishers for 26.0%. Inside beauty conversations, retail and e-commerce sources supplied 54.7% of citations. Inside travel, reviews and user-generated content supplied 54.1%. Inside finance, specialist finance sources accounted for 36.6%.

Aleyda Solis, founder of Orainti, is quoted in the report identifying a disconnect between cited pages and pages receiving traffic. According to her analysis in the report, 65% of cited URLs sit two or three folders deep, with folder depth two alone accounting for 41.7% of citations, while 58.8% of AI referral traffic lands on homepages. Solis argues in the quoted passage that cited pages and traffic pages serve different purposes and should be assessed separately.

The May 7 ChatGPT update

The homepage concentration is recent. Similarweb attributes it to a ChatGPT search update on May 7, 2026. In the weeks that followed, indexed referral volume roughly doubled while the proportion of referrals landing on homepages rose from around 25% to close to 60%.

The pitch accompanying the report puts the figures at 60% and 27% respectively; the report's own chart shows approximately 25% before and just under 60% after. Either way, the practical effect is the same: ChatGPT began functioning less as a deep-link source and more as a gateway to brand front doors.

Referral volumes by industry, worldwide for June 2025 to May 2026, put marketplaces at 46.8 million, news at 44.5 million, travel at 44.5 million, finance at 19.1 million, consumer electronics at 17.1 million, fashion at 7.1 million and beauty at 2.0 million. Growth rates run inversely to base size: beauty grew 312.5%, fashion 278.2%, marketplaces 237.3%, finance 236.5%, consumer electronics 215.4%, with news and travel both at 115.6%.

Those absolute numbers deserve proportional reading. Chartbeat data published in March 2026 showed small publishers lost 60% of search traffic over two years while ChatGPT referrals stayed under 1% of total publisher page views. Similarweb's own category chart shows news as the only major web category to shrink over the period, down 5% to 1.4 billion average monthly unique visitors, while AI chatbots grew 57% to 650 million.

Harry Clarkson-Bennett, Partner at DJB Strategies, is quoted in the report saying that news and publisher sites need to find new ways to attract and maintain audiences in the era of AI, with a focus on audience engagement, loyalty and less expectation on traditional channels giving back the same results.

Advertising inside the answer

The report's advertising section carries the sharpest numbers for media buyers. ChatGPT ad penetration reached 26% of US desktop chats in June 2026, against 14% in May 2026, according to the summary page. Measured as the share of conversations containing ads across markets between April and June 2026, the US line ran near 10% in early April before climbing above 30% by late June. Australia and Canada followed similar curves with a later start. The UK line moves sharply upward from near zero in early June. Japan starts near zero and reaches roughly 10% by late June.

That rollout sequence matches the geographic expansion PPC Land has tracked: ChatGPT ads went live in the United Kingdom on June 6, 2026, followed by Japan and South Korea.

The Adthena discrepancy resurfaces here. Adthena recorded zero ad placements across 169,560 UK ChatGPT scrapes during June 2026. Similarweb's chart shows UK ad penetration rising above 30% during the same month. Two commercial measurement firms describe the same market in June 2026 in incompatible terms, and neither has published the methodology detail needed to resolve it.

Similarweb's top ten US ChatGPT advertisers for June 2026 lists Resume.io, Monday.com, Framer, Axon by AppLovin, Attio, BestMoney, Aikido Security, SAP, Home Depot and VistaPrint. The composition skews heavily toward software and services rather than the retail brands that dominate paid search.

Behavioural metrics on the ad unit itself: 66.3% of ChatGPT ads appear after the second prompt or later, 65.3% of sessions continue after an ad appears, and the click-through rate sits at 0.50%. Harel Amir, General Manager of Ad Intelligence at Similarweb, is quoted describing conversational advertising as fitting inside the user's journey rather than breaking into it.

That 0.50% figure sits below the 0.68% overall click-through rate Similarweb data produced in May 2026, reported at the time alongside OpenAI's broader US rollout. As inventory scales, average click-through appears to be compressing rather than holding.

Downstream effects on brand visits

Similarweb measured what happens after an AI recommendation across three verticals between July and December 2025. In finance, users who received an American Express recommendation visited that brand at 7.2% against 3.1% for Capital One; when the recommendation reversed, Capital One drew 14.2% against 3.8%. Travel showed Skyscanner at 9.5% against Kayak at 7.6%, and Kayak at 12.0% against Skyscanner at 3.4% when recommended. Beauty showed Sephora at 7.9% against Ulta at 3.3%, and Ulta at 7.6% against Sephora at 4.6%.

The recommended brand received two to four times the subsequent visits of the unrecommended competitor across all six comparisons. This extends work PPC Land covered in June 2026, when Similarweb traced AI recommendations to real traffic and found recommended brands 2.5 times more likely to receive a site visit within seven days.

Rand Fishkin, founder of SparkToro, is quoted in the report comparing the data to how twentieth-century advertisers measured billboard, television and radio impact through lift in store visits, and arguing that marketers must change how they run measurement and attribution.

Brand visibility rankings for beauty, indexed to the category leader in May 2026, place CeraVe at 100, Ulta at 86, Sephora at 80, La Roche-Posay at 74, The Ordinary at 67, e.l.f. Cosmetics at 33, Maybelline at 23, NYX at 19, and Paula's Choice and YSL Beauty tied at 17. The same beauty names dominate Amazon's Alexa for Shopping referral rankings, where CeraVe again leads. Amazon PDP views originating from that assistant, indexed to June 2025, peaked above 700 in December 2025 before settling around 500 through spring 2026. Amazon merged Rufus into Alexa for Shopping on May 13, 2026.

Why this matters for marketers

Three things follow from the dataset with reasonable confidence.

First, single-platform tracking is no longer sufficient. When ChatGPT's web share falls from above 80% to near 50% in twenty-four months, and 95% of its users also use Google, a visibility programme built around one surface measures a shrinking fraction of the discovery landscape.

Second, the citation-versus-referral split is a measurement problem before it is an optimisation problem. Pages that earn citations and pages that receive clicks are largely different pages, and reporting that treats them as one number obscures both.

Third, the measurement disputes are as material as the findings. A 43% AI Overview frequency and an 18% AI Overview frequency cannot both describe the same US search market in mid-2026. UK ChatGPT ad penetration above 30% and 0.00% cannot both be true for June. Similarweb notes in its own disclaimer that its data are estimations and extrapolations based on source materials obtained from third parties, and are not warranted for accuracy or completeness. Any budget decision anchored on a single vendor's panel inherits that uncertainty.

The report is also a commercial document. Similarweb sells the intelligence products whose necessity the findings establish, and three separate demo prompts appear inside the deck. That does not invalidate the panel data, but it does place the report in the category of interested-party research.

Timeline

Summary

Who: Similarweb, a digital intelligence company, published the report. It was authored by Laurie Naspe, Director of Market Insights, and Sam Sheridan, Data Analyst, with contributions from Similarweb executives including Baruch Toledano and Harel Amir, and quoted commentary from external practitioners including Harry Clarkson-Bennett, Michael Horrocks, Ethan Smith, Kevin Indig, Rand Fishkin, Lily Ray and Aleyda Solis. The findings concern ChatGPT, Gemini, Claude, Perplexity, DeepSeek, Grok, Microsoft Copilot, Meta AI, Google AI Overviews, Google AI Mode and Amazon's Alexa for Shopping.

What: The 2026 Generative AI Landscape report documents 9.5 billion average monthly web visits to generative AI platforms, 655 million monthly unique visitors, ChatGPT's declining share of standalone chatbot web visits, AI Overviews reaching 43% of US searches, ChatGPT citation rates rising to 6.8% of answers, a post-May 7 shift toward homepage referrals, and ChatGPT ad penetration at 26% of US desktop chats with a 0.50% click-through rate.

When: The report was published today, July 22, 2026. Its datasets cover periods from June 2024 through June 2026, with the advertising data extending to the end of June 2026 and the audience affinity data drawn from October 2024 to September 2025.

Where: Measurements span worldwide desktop and mobile web, US-specific desktop panels, and iOS and Android app data. Advertising penetration data covers the United States, Canada, Australia, the United Kingdom and Japan.

Why: The report matters for the marketing community because it quantifies fragmentation across AI discovery surfaces at the moment advertising is scaling inside them. Single-platform visibility tracking now covers a shrinking portion of the market. The gap between pages AI systems cite and pages that receive clicks complicates performance reporting. The divergence between Similarweb's figures and competing measurements from Adthena on both AI Overview frequency and UK ChatGPT ad presence indicates that no settled measurement standard yet exists for the channel, which carries direct consequences for how confidently budget can be moved against it.