Perma.cc is a web archiving tool created by the Harvard Law Library and the Harvard Innovation Lab. In a study they conducted, Harvard found that 70% of the links in law review and journal articles and 50% of the links cited in USSC court opinions were broken. When a user creates a Perma.cc link, Perma.cc archives the referenced content and generates a link to an archived record of the page. Regardless of what may happen to the original source, the archived record will always be available through the Perma.cc link.
Bluebook Rule 18.2.1 (d) calls for archiving of internet sources but only when there is a reliable archiving tool. In the examples provided there is an example for when Archive-It is used and when Perma.cc is used. Perma.cc is used when an author cites to an internet source you are editing and when you rely on an internet source.
The Law Library has an Institutional account with Perma.cc that allow us to add unlimited users/organizations to input unlimited links into the system. Please contact at reference librarian to set up your Perma.cc account and get training on the service.