The focus of the Hiberlink project is to assess the extent of so-called ‘reference rot’. This two-year study investigates how web links in online scientific and other academic articles fail to lead to the resources that were originally referenced. Herbert Van de Sompel
The HTTP-based Memento framework bridges the present and past Web. It facilitates obtaining representations of prior states of a given resource by introducing datetime negotiation and TimeMaps. Datetime negotiation is a variation on content negotiation that leverages the given resource's URI and a user agent's preferred datetime. TimeMaps are lists that enumerate URIs of resources that encapsulate prior states of the given resource. The framework also facilitates recognizing a resource that encapsulates a frozen prior state of another resource.
WebCiteBOT's purpose is to combat link rot by automatically WebCiting newly added URLs. It is written in Perl and runs automatically with only occasional supervision.