Permanent URLs from Archive.org
The concept is dead simple: Give the archive a URL that you think might move in the future, and they will give you a new url that redirects to the content in question. If that content does indeed move in the future, just log in to purl and update your re-direct. Easy Peasy, and nothing breaks.
This is a great way to mitigate the problems inherent with hosting your content through a third party, and is a lot safer for links that will be spread out all over the internet (assuming, of course, that the internet archive doesn’t suddenly go under, in which case we’ll have bigger things to worry about anyway.)