Now Knut has written a fine fe-renderer to achieve this: moving outdated articles into an archive automagically. Here is the gem:
http://www.phpwcms-howto.de/wiki/doku.p ... -in-archiv
http://www.phpwcms-howto.de/wiki/doku.p ... to-archive
While discussing this I thought if it wouldn't be a good idea to have it implemented into the core - article basis information with some checkboxes / switches or so, where you can define an archive target folder (similar to News e.g. where it is targeted via tags - great feature by the way) and whether the killdate should be extended to see it in an article menu also (there too is a script out already to have listed an outdated article within an article menu CP)
Until now you have to move it manually (without Knuts script) and the only advantage of the "visible after end date" checkbox is for search engines, but not for humans.