As we've discussed a number of times on Slaw, a good many hyperlinks break over time as their targets get moved or taken down. This link rot is particularly challenging in academia and in law, where cited authorities are an important component of one's argument.
In a 16 page document available on SSRN three weeks ago, "Perma: Scoping and Addressing the Problem of Link and Reference Rot in Legal Citations," Harvard professors Jonathan Zittrain and Kendra Albert:
. . . document a serious problem of reference rot: more than 70% of the URLs within the Harvard Law Review and other journals, and 50% of the URLs found within U.S. Supreme Court opinions do not link to the originally cited information.
Given that, we propose a solution for authors and editors of new scholarship that involves libraries undertaking the distributed, long-term preservation of link contents.
(The study — more of a "spot check," as the authors call it — only looked at "open web" links and ignored links to proprietary databases such as LexisNexis or Westlaw.)
The solution proposed is perma.cc,
a service, currently in beta, that allows users to create citation links that will never break.
When a user creates a Perma.cc link, Perma.cc archives a copy of the referenced content, and generates a link to an unalterable hosted instance of the site. Regardless of what may happen to the original source, if the link is later published by a journal using the Perma.cc service, the archived version will always be available through the Perma.cc link.
Readers who click on a Perma.cc link are taken to a page that lets them choose to go to the original site (which may have changed since the link was created) or see the archived copy of the site in its original state.
Perma.cc is an online preservation service developed by the Harvard Law School Library in conjunction with university law libraries across the country and other organizations in the “forever” business.
There are currently 27 law library partners in the perma.cc collective, none Canadian yet, I'm sorry to say.