Link Rot is what happens to the outbound links on a website, after the link has been up for a while, the years fly by, and the page the link pointed to no longer exists (404), has been redirected (301 or 302), or put behind a paywall (503) or no longer contains the content you were originally linking to. Sometimes sites get hacked and start delivering malware to visitors... and you don't want to continue linking to those kinds of pages from your site. One should occasionally do some link pruning and get rid of these bad outbound links using a crawling tool such as Screaming Frog.
Celebrating 25 Years of Creating an Island of Stability In the Sea of Online Confusion
