Now, mailman, does things on a regular basis by adding to the crontab. I got a mail today from a user who was apparently not getting his mailman digests (only just signed up), but got some direct responses, so knows his post was successful, and there was blatantly traffic happening. Imagine my surprise when I discover that the mailman cron jobs are nowhere to be found. Oh the irony, that 'cron job' Bob of all people would forget the cron jobs for mailman. Admittedly this was a Solaris install, so the init script wasn't dealing with them automaticlly.
And the reason the LDAP server was grinding to a halt... A cron job to keep two ous in sync was going bananas and stealing all the memory, swap and CPU time. *bangs head against wall*
 And yes this does mean that if you got root on one of the client servers (this included a number of desktop machines) then you got root on the entire department system.