A link that gives a “404" “file not found” result because the page has been moved or renamed.
if a list of links is not maintained, its usefulness will erode as the linked sites move, disappear or update their content so that it is no longer relevant. Section 3.1 discusses how to combat this process.
When you create a website, you can provide links from your site to useful information on other sites. This saves you, and your users, lots of time, and, if done well, can add real value to your site for your visitors. However, sometimes the pages you link to disappear, or are moved. This causes linkrot - the link on your site no longer lead anywhere. Good designers minimise linkrot by doing two things: keeping content permanently located (disk space is cheap, after all, and just because I don't find a particular document useful anymore doesn't mean other people aren't referring to it), and checking off-site links on a regular basis as part of site maintenance.
What happens when links go bad over time, either because a Web site has shut down or a site has stopped supporting a unique landing page provided in an email promotion.
The general breakdown of links either among Web pages or from email newsletters to Web sites because the sites have shut down, changed addresses or removed or reorganized pages.
That which happens to hypertext and hypermedia links when people move or remove files on Web servers without providing links to new file or server locations. Some files pointed to in URLs just disappear. A feature of bad Website maintenance, but also an inevitability of the globally distributed and dynamic system of the Net and Web.