So I've had to completely rebuild my 'blog database.
Unfortuately all of the entry IDs got renumbered.
This means that none of the favorites, and none of the links from one entry to another, will work correctly until I get it all sorted out.
Sucks to be me.
(Update: Problem fixed. Sorry for any inconvenience this may have caused. Search sites that have the old entry IDs cached will get caught up eventually I guess.)