2011 Apr 30, 4:33
"The HTTP-based Memento framework bridges the present and past Web by interlinking current resources with resources that encapsulate their past. It facilitates obtaining representations of prior
states of a resource, available from archival resources in Web archives or version resources in content management systems, by leveraging the resource's URI and a preferred datetime. To this
end, the framework introduces datetime negotiation (a variation on content negotiation), and new Relation Types for the HTTP Link header aimed at interlinking resources with their archival/version
resources. It also introduces various discovery mechanisms that further support briding the present and past Web."