del.icio.us Link Checker
I’ve written a short Perl script that, when run locally with your credentials, will retrieve all your del.icio.us bookmarks and attempt to verify if they still exist or not.
The Delicious Link Checker is written in simple Perl and should be quite easy to customise. I’ve added a (now deprecated) Delicious Link Checker home page that contains the notes, the next batch of TODO tasks and other miscellaneous bits of information.