Web Science and Digital Libraries Research Group

Figure 1: Snopes.com has no public captures on the Internet Archive’s Wayback Machine prior to October 2021. Snopes.com is a well-known fact checking website. It has been rated trustworthy by multiple rating organizations [1]. However, in 2021, BuzzFeed broke a story that, in fact, Snopes was plagued by plagiarized articles, and that authors were being told to plagiarize and then silently make updates to their articles after publication in the name of SEO . One of the byproducts of the BuzzFeed investigation is that there are no publicly available captures of Snopes.com in the Wayback Machine prior to 2021. Snopes’s official statement regarding this is that the founder, who was named responsible for the plagiarism, had a policy against Wayback captures; but, now that he was removed from duty, the board was going to change the policy going forwards. In fact, having no captures before 2021 means that the archives available give a more trustworthy historical view of Snopes.com than ex...

  The CDC ACIP vaccine recommendations page includes a human-readable (left) and machine-readable (right) last updated date.  In early 2025, US federal websites were undergoing rapid changes with the new presidential administration. In February 2025, we analyzed the rate of page deletions across administrations, and further analyzed the content of changed CDC pages in summer 2025. One surprising thing that we found was that while CDC pages contained a “last updated” date, many of the dates were incorrect: pages contained silent, unannounced updates, generally related to relevant executive orders. How does trustworthiness change over time? Silent, unannounced changes that do not match the last modified date of a webpage reduce the trustworthiness of the page. We can study three different change markers: the HTTP last-modified property , meta tags that contain last updated information, and text on the page that is viewable to the user containing update information. These mar...