rev=canonical: url shortening that doesn't hurt the internet revcanonical.appspot.com · Archived on 18 Jun 2009 · Originally posted on Pinboard

RevCanonical is url shortening with a twist. Instead of creating its own super short versions of links, it checks to see if the link owner has published a shortened version of the given page using HTML link element. If not, we just return the original URL. And you should bug the link owner about providing a better alternative.