Q:

Link Rot: Encourage author to cache snippets of relevant text to prepare for this eventuality

I have withdrawn this from being a feature-request to just a discussion (as recomended by @arjan).

What I would like to propose is more awareness of the fact that Links Rot, and so should only preferably be used as sources (as pointed out by @jmort253)

Original Post
Link Rot, unlike a zombie attack, will happen! So why not prepare for it?
Allow user's to add meta (read rot-friendly) information to links. It is like a cache of a subset of that links' content which will probably come in handy when the link rots.
Over the last couple of occasions I have tried to add as much meaningful information to a link as possible, thus creating an automatic fall back lest the link ceased to exist.
I have used the following 3 ways:

Linking the complete link text: https://stackoverflow.com/a/11030548/476786
Providing a meaningful/keyword handle: https://stackoverflow.com/a/10377355/476786
Including a relevant snippet from the linked page in the answer with a disclaimer: https://stackoverflow.com/a/11379888/476786 and https://stackoverflow.com/a/11605402/476786

Now, the first 2 approaches are acceptable when either the link text and/or the keywords are small enough in length while still providing enough info to fuel/guide a search.
But the 3rd approach got me thinking about <die>copyright</die>. What about sites that forbade you to copy content across? I'm not legally knowledgeable enough, but clearly this would be a violation, yes?
Why not then have something like a <rot /> markup, quite similar to spoilers, but semantically more relevant. For the copyright part, this text should be kept hidden until the SO bots that check links flag it as unavailable. Once this threshold has been met, the text can be shown with whatever disclaimer you see fit. Let this be a reversible task for links that rise from the dead.
My visualization of the feature relies on the OP or the answerer making the effort. I of-course welcome a better or more unobtrusive way to do this, as long as something is done.

A:

What about sites that forbade you to copy content across?

Don't copy it. Paraphrase it. If you're linking an article that you feel answers the question, you should be able to explain what the article says and how it answers the question. That's the kind of context we want to be included with links. Links aren't there as a "go here for the answer" catch-all, they're a way to provide a source of where you got the information you're now providing.
If it's a code example that you need to provide, make up your own. It's extremely difficult to copyright code snippets, since it's very possible for someone to write code which is almost exactly the same, especially when you get into simple code statements which are used all the time. Use snippets of the code which are relevant to the OP. In some cases, you can integrate the pieces the OP needs with the code they already have.
A feature to provide context about a link after it dies is not necessary, as the context should have already been provided a long time ago with the answer. Copyrighting is only a problem if you're, well, copying. Most sites will already allow you to copy content as long as you provide a link back. If you're ever not sure, take a visit to a chat room and ask someone.

