What Wikipedia Reveals About AI Overviews And Web Traffic

A College of Washington working paper now estimates that Google’s AI Overviews decreased month-to-month search referrals to English Wikipedia by roughly 5% after the function turned the U.S. default in 2024. The paper, by Mehrzad Khosravi and Hema Yoganarasimhan, was final up to date on September 2 and hasn’t been peer reviewed.

The newer estimate took the place of a bigger one which the identical authors printed again in February, and this revision is all a part of the story. Google disputes whether or not the mixed referral metric can isolate its function.

Wikimedia says many individuals entry its volunteers’ work via AI and search instruments with out visiting wikipedia.org. The revised paper explores a particular facet of this, how default AI Overview availability influenced referrals from exterior serps.

Wikipedia Provides A Uncommon Site visitors Take a look at

Wikimedia releases month-to-month clickstream information on the article stage for numerous Wikipedia language editions, comparable to English, German, and French. These recordsdata categorize exterior serps collectively and omit referrer-article pairs with low quantity. The authors examined a number of values for the suppressed post-treatment counts and reported almost similar estimates.

Google switched AI Overviews on by default in america in Could 2024. In keeping with the paper, it hadn’t but achieved so in Germany or France through the pattern interval. The authors see language editions as a option to symbolize completely different areas. Through the pattern interval, about 40% of visitors to English Wikipedia got here from america. In the meantime, visitors for German and French editions principally got here from nations with out default AI Overviews. If, after Could 2024, English referrals fell in comparison with German and French referrals for a similar articles, that distinction is the estimate.

The information covers the interval from December 2023 to December 2024. The authors contemplate Could 2024, when the U.S. rollout began, as the primary post-treatment month. The panel consists of 499,927 matched English-German article pairs and 530,873 English-French pairs. They used a Poisson pseudo-maximum probability difference-in-differences mannequin, which helps estimate proportion modifications in counts. The authors estimate that default AI Overview availability decreased month-to-month external-search referrals to English Wikipedia by 5.45% relative to German and 4.82% relative to French.

For the English version as an entire, the estimate works out to round 100.27 million fewer search referrals every month, totaling about 1.20 billion yearly. The month-to-month quantity is model-based, and the yearly estimate assumes this impact stays constant all year long. Each figures account just for direct referrals from serps, not all visitors Wikipedia receives.

Earlier variations used every day pageviews and reported a decline of about 15%. The paper then switched to month-to-month search referrals and added German and French controls in v5 on August 26, with extra updates in v6 on September 2.

An English-Japanese test within the present model exhibits a 16.53% decline, utilizing a shorter timeframe and a unique comparability group. The authors observe that this result’s directional assist solely.

What The Estimate Does Not Show

Wikimedia’s public information lumps all exterior serps collectively, a limitation the paper acknowledges. Google told UOL Tilt that this prevents the evaluation from isolating Google, however Yoganarasimhan mentioned different engines deal with solely a small portion of visitors, and the evaluation makes use of the timing break created by the AI Overviews rollout.

This estimate addresses a particular query. It measures what occurred to referrals when English-language readers have been in an setting the place AI Overviews have been on by default. The sooner experiment I discussed in April confirmed an even bigger drop when AI Overviews appeared throughout searches. So, whereas associated, they’re completely different findings.

It counts referrals from serps made by human readers, so if somebody arrives from Google after which reads three extra articles, it counts as one go to. Most of English Wikipedia’s guests come from outdoors the U.S., which waters down the measured impact. Plus, the design can’t fully rule out different 2024 occasions affecting English search however not German or French search.

The income estimate must be seen with care. The authors calculate {that a} comparable ad-supported web site may lose someplace between $10.82 million and $37.08 million every year at typical advert charges. Since Wikipedia itself doesn’t show adverts, this determine is solely hypothetical and doesn’t symbolize Wikimedia’s actual funds or any funds moved to Google.

Lastly, the paper doesn’t look into long-term results, so it doesn’t present insights into modifying exercise, donations, or whether or not fewer visits may affect future content material creation.

Wikimedia Sees A Wider Site visitors Change

The Wikimedia Basis’s information provides a unique perspective. In October 2025, product director Marshall Miller shared that total human pageviews throughout all Wikipedia languages had decreased by about 8% in comparison with the identical interval in 2024. This info got here after Wikimedia improved its bot detection and reclassified visitors from March via August 2025. Visits spiked and appeared to come back from actual customers, primarily from Brazil, however a lot of that visitors was pushed by bots designed to bypass detection.

Miller attributed the decline to generative AI and social media platforms. Nonetheless, he additionally identified that the relabeled information must be seen with some warning as a result of detection strategies have modified over time. That is about total human pageviews, not a causal estimate about AI Overviews, so it might probably’t be added to the paper’s 5% estimate.

I discussed this update again in October. By April, the Basis’s draft plan for the 2026-27 fiscal 12 months highlighted that reducing pageviews and fewer referrals from Google, together with bot visitors the plan calls unprecedented, are anticipated to proceed reasonably than be short-term points. The plan additionally notes that nearly 90% of Wikipedia guests have historically come from Google search.

Machine Demand Retains Rising

In April 2025, the Wikimedia Basis’s engineers observed that the bandwidth for downloading photos and media recordsdata went up by 50% since January 2024. Most of this improve got here from bots scraping Wikimedia Commons for AI coaching reasonably than from common readers. Additionally they famous that bots accounted for at the very least 65% of the most costly visitors, which reaches the core information facilities, and about 35% of pageviews.

A 12 months later, the crew mentioned they have been blocking or limiting round 30% of those automated requests from crawlers that ignore their insurance policies, and a chart observe put blocked or throttled requests at about 1.5 billion a day. The report explains that some bots imitate common browsers or use proxies through house web connections. The intention is to information large-scale reusers towards channels the place they will determine themselves and obtain larger limits, reasonably than to cease reuse.

None of this exercise seems in referral counts. Whether or not it’s a crawler copying an article for coaching, a search engine quoting it in an AI response, or a reader clicking via from that response, all these actions are thought-about separate occasions. Solely the click-throughs are counted as human external-search referrals within the paper’s final result.

Quotation, Visits, And Enterprise Entry

Pew’s evaluation found that folks hardly ever clicked on sources inside AI summaries. They checked out 68,879 Google searches from March 2025, which got here from the searching exercise of 900 U.S. adults. They repeated the searches from April 7 to April 17 to seize the consequence pages, which means the AI-summary classification relies on these later information. When visits included an AI abstract, individuals clicked on conventional outcomes 8% of the time, in comparison with 15% when no abstract was there. Only one% of visits to pages containing an AI abstract led to a click on on a supply inside it. Wikipedia, YouTube, and Reddit collectively made up 15% of cited sources, though Pew didn’t specify Wikipedia’s precise share.

Google’s personal documents say that AI Overviews information customers to a broader vary of internet sites. Liz Reid’s August 2025 blog post shared that the full natural click on quantity stayed “comparatively steady” in comparison with the earlier 12 months, despite the fact that she didn’t present precise numbers. She additionally mentioned this on Bloomberg’s Odd Tons podcast in April.

In November 2025, the Basis urged AI builders to correctly credit score Wikipedia of their outputs and requested them to entry it via Wikimedia Enterprise. They imagine giving credit score encourages a cycle by which readers turn into editors and donors, however in addition they warn that fewer visits may result in fewer volunteers and donors.

Wikimedia Enterprise is the Basis’s paid service that gives high-volume API access, together with contracts, uptime ensures, assist, and structured information feeds. It fees for entry, not the content material itself, which stays freely out there via public channels underneath open licenses, topic to its license phrases. Lane Becker, who oversees this system, shared in July that this mannequin relies on entry reasonably than licensing. The revenue from Enterprise is capped at 30% of the Basis’s annual income, he mentioned, and the unit reported $8.3 million in income for the 2024-25 fiscal 12 months.

In January, Wikimedia Enterprise announced that Google is an present buyer, and for the primary time, Amazon, Meta, Microsoft, Mistral AI, and Perplexity have been launched as companions. In July, Wikimedia Enterprise announced GNOMI as one other companion. Wikimedia describes Enterprise as a paid service designed for high-volume entry and assist, reasonably than compensation tied to referral losses.

Why Wikipedia Is An Uncommon Take a look at

The options that make Wikipedia measurable additionally restrict how broadly its findings can be utilized. Wikimedia shares information on articles in lots of languages, and the paper compares matching pages throughout completely different language editions. Most web sites don’t have the power to make these sorts of comparisons.

The paper doesn’t set up whether or not information websites, retailers, or different varieties of web sites would expertise comparable results. Moreover, the sources don’t deal with whether or not different organizations may create a paid entry service just like Wikimedia Enterprise.

Wanting Forward

This paper remains to be a working paper, rebuilt as soon as and revised a number of occasions since February, so the figures are the most recent estimates, not ultimate numbers. We’ll replace if new figures from the authors, Wikimedia, or Google change the image.

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