The Internet Archive, Home of Dead Links

You can try to prevent material 'disappearing' from the internet, at least as far your
personal use of it is concerned, by archiving it in the manner described above. However,
what do you do when you hit a dead link? In other words, what do you do when one
internet document refers to you another, but that document is no longer available?
Sometimes this happens when an institution re-structures its website – suddenly the links
won't work any longer. In such cases, you may be able to use the internal sitemap or
search mechanisms of that website to locate the document you are looking for. This is
certainly the preferable method, for this will allow you to find the most current version of
the document you are looking for.