The internet is full of all manner of unsavoriness that is surely corroding our minds and societies. But the kind of rot we’re talking about here is link rot — the disappearance of online content when links turn into “404 Page Not Found.” A recent study from Pew Research suggests almost 40% of all webpages that existed in 2013 are no longer accessible. That includes important government links, citations on Wikipedia and hyperlinks in news articles. Marketplace’s Lily Jamali recently talked about this with Clare Stanton, product and research manager at Harvard Law School’s Library Innovation Lab, who also works on a webpage preservation project, perma.cc.