A system that can be configured to detect spammers.
No legitimate user should be able to post more than 2 or 3 comments or reviews within a minute or so. The system would need to watch for repeated post attempts within the a specified time, both admin configured, and then block that user/IP according to the admins settings. If a block is made then any comments or reviews that were successful should be put into moderated status for an admin to review. In case of an accidental block then a quick one button "release" for all the moderated messages for a particular user/IP would make it easy for the admin to clear a user.
IP's should be displayed to the admin for all comments and reviews in order to help manage any troublemakers.
http://www.FicSavers.Com
http://www.HPFanFicArchive.Com
http://www.FavoritesTracker.Org
I guess that kind of falls together with the other anti-spam/moderation issue, surely a trusted member's account could also be compromised - anybody else has any ideas concerning this?