I'd really like to do this in sieve somehow. I don't know if you can.
Code:
MONTHFOLDER=`date +%Y.%m`
:0 # LogWatch and other log reports
* ^Subject.*LogWatch for
.Servers.logs.${MONTHFOLDER}/
:0 # Cron jobs
* ^(From.*Cron|Subject.*Output from)
.Servers.cron.${MONTHFOLDER}/ Zimbra touts the whole tagging concept and tries to downplay folders, but they aren't going away and neither are IMAP clients. So folders will remain necessary. New features come fast and furious, so I haven't lost hope yet.