I suggest that a tool for dead links management is introduced, maybe as a plugin.
Links are a really valuable part of every site, maybe the most important component on a http experience. They allow navigation and often are a big part of the content itself.
The whole Internet is continously evolving and things change; and links go dead.
Sites gain (or loose) value due also to the links they provide to the user. It is important that the site manager (and/or the content's author[s]) be alerted when links die.
There should be some sort of tool that on a time basis (every night or two) tests all the links within a site, and mark them as:
a) live (default)
b) sick (when unreachable twice)
c) dead (when unreachable >= three times)
As a link is marked "dead", an email notification is sent to the person who posted it (and/or the site admin).
An admin page could also be set up, to list on the fly either live, sick or dead links and their location.
Such an (arguably) simple script could greatly help and enhance a site value over time.