On 14 March and 15 March 2018, a CentralNotice banner appeared to some logged-out users viewing English Wikipedia pages. The banner contained JavaScript hosted by Facebook, which allowed Facebook to collect traffic data from those who visited a page with a banner. The banner was prepared by the Wikimedia Foundation. The Foundation turned the banner off as soon as we learned how the script was running, and its potential scope. We have also removed all references to the code in question from CentralNotice on Meta-Wiki.
The code utilized in this banner was based on an unused prototype created by an outside vendor. Because the prototype was never enabled, the vendor’s prototype code was not subjected to our standard quality assurance process. However, we made the mistake of reusing the code for a different purpose, and implementing it based on recommendations in documentation from Twitter and Facebook to improve the appearance of shared links. At the time, our understanding was that the platforms would only receive traffic data if the user clicked on the link. Although this was true for Twitter, the Facebook code operated differently. We discovered the problematic link configurations during our ongoing monitoring of live banners. The recommended code enhanced not only the appearance of links, it also enhanced Facebook's ability to collect information on people visiting non-Facebook sites. As soon as we realized these banners were sharing information without even having to click the link, we disabled them and began an investigation. Staff in multiple departments are collaboratively reviewing the incident as well as procedural and technical improvements to prevent future incidents. While this sort of tracking is commonplace today across most of the internet, it is not consistent with our policies. We are disappointed that this type of hidden data collection is routinely recommended by major platforms, without clearer disclosure. These practices are why we all must regularly take routine steps to maintain a secure computer and account. As the Wikimedia Foundation continues to explore ways we can do that within Wikimedia's platform, we encourage you to consider tools which block unwanted third-party scripts like the one provided by Facebook. We apologize for sending this late on a Friday (San Francisco time). However, we wanted to provide this information as quickly as possible. _______________________________________________ Wikimedia-l mailing list, guidelines at: https://meta.wikimedia.org/wiki/Mailing_lists/Guidelines and https://meta.wikimedia.org/wiki/Wikimedia-l New messages to: Wikimedia-l@lists.wikimedia.org Unsubscribe: https://lists.wikimedia.org/mailman/listinfo/wikimedia-l, <mailto:wikimedia-l-requ...@lists.wikimedia.org?subject=unsubscribe>
