Web Of Trust browser add-on, downloaded over 140M times, pulled from Mozilla, Chrome, Opera add-on stores after it was caught selling users' browsing histories
Uninstall It Now Martin Brinkmann / gHacks Technology News : Mozilla and Google remove WOT extension from Store Lee Mathews / Forbes : Web Of Trust Browser Add-On Blasted For Breaking User Trust Vlad Dudau / Neowin : Safe browsing Web of Trust add-on was accidentally selling user data, e-mails, phone numbers Matthew Humphries / PC Magazine : ‘Web Of Trust’ Browser Extension Cannot Be Trusted Office of Inadequate Security : Web of Trust (WOT) Add-on taken down by Chrome & Firefox Thorin Klosowski / Lifehacker : Web of Trust Sells Your Browsing History, Uninstall It Now Spyware Sucks : Web of Trust (WOT) scandal Tweets: Privacy Matters / @privacymatters : Reporters buy web browsing history of 3 million people inc 10 billion URLs & re-identify some users http://www.ghacks.net/... Privacy Matters / @privacymatters : Data contained more than ten billion URLs http://twitter.com/...
Context & Ripple Effects
Web of Trust built its 140M-install base by rating site trustworthiness from the browser — which meant it could see everything its users browsed. German TV reporters bought that history back: records covering three million people and over ten billion URLs, complete with emails and phone numbers, and re-identified real users from them.
The takedown by Mozilla, Google and Opera is the template case for a failure mode that keeps recurring: extensions leaking names and passwords to marketing intelligence in 2019, Google removing 106 malicious extensions with 32M downloads in 2020, and researchers finding 245 extensions overriding security protections to scrape sites for a paid service in 2025.
First-order effects
- Mozilla, Google and Opera pull Web of Trust from their stores, forcing up to 140M users to uninstall an add-on they installed precisely because it promised safety — while WOT loses its entire distribution channel and the browsing-history revenue stream exposed by the reporting.
Second-order effects
- Store operators face pressure to audit what extensions do with collected data rather than just what permissions they request, since WOT's data sales were invisible at install time; buyers of the history data now hold re-identifiable records on millions of people with no consent chain behind them.
Third-order effects
- If the pattern holds across the later removal waves, browser vendors become de facto privacy regulators for the extension economy, shifting enforcement from user vigilance to platform-level review of how trusted tools monetize the data they observe.
The trend: Browser extensions keep converting privileged visibility into users' browsing into a data business, pushing Chrome, Firefox and Opera toward policing data practices rather than trusting permission labels.