09/12/2026
https://www.facebook.com/share/p/1CcyAPBP45/
An updated study shows that AI Overviews reduced search referrals to English Wikipedia by around 5%. The same study originally put it at 15%.
The number moved because the measurement changed.
Earlier versions of the paper tracked daily pageviews. The current version tracks monthly search referrals and compares English articles against the same articles in German and French, neither of which had AI Overviews on by default during the sample period.
That switch is what took 15% down to 5.45% against German and 4.82% against French.
5% might sound fractional, but it amounts to around 100 million referrals a month, roughly 1.2 billion a year.
Google still disputes it.
Wikimedia's public clickstream data groups every external search engine into a single bucket, so the paper cannot separate Google's contribution from anyone else's, and Google's position is that this makes it impossible to attribute the decline to AI Overviews specifically.
The authors counter that rival engines handle only a small share of that traffic, and that the analysis leans on the timing break created by the U.S. rollout rather than on isolating Google by name.
The wider trend is not really in dispute, though. Whatever is going on here highlights that there is a shift in traffic online, and it is hitting large publishers like Wikipedia hard.
The industry quoted 15% for months without much interest in how it was derived, and will now quote 5% the same way.
Matt Southern has the full breakdown. Link in comments.