Currently, links to messages don't get journalled 
because the journal files were expanding out of control. 
One of the major reasons for this was the dumb journal 
file format. Fixing that should allow us to re-enable the 
link journalling, and allow links back from messages to 
their issue (for example).  
  
At a minimum, this would involve changing the  
journalling to only record the additions/deletions for a  
multilink, rather than the whole multilink list each time.