URLs in letter cross-refs

Steve Outing has echoed one of my personal hobbyhorses in E-Media Tidbits: print URLs of original stories on letters (and corrects & clarifications). Two points: 1, you'd have to use a service like TinyURL to provide nice, short URLs that people can type (unlike our Vignette monstrosities); 2, if you run cross-refs in Corrections and Clarifications, how does this affect the policy pertaining to the original story online? Do you append the correction to the bottom? Do you correct the story? How do you tackle repeated corrections? And what of those cases where you're legally obligated to remove the story altgether?
(From E-Media Tidbits)