Moderators should be able to email a user to tell them why their idea has been rejected. Some perfectly good ideas have to be rejected because of one use of bad language, because the user posts their personal details etc. The user may have no idea why their idea hasn't appeared on the site - this can lead to frustration and moderators being accused of draconian censorship.

Users are required to submit an email address when they subscribe to the site, so there should be no difficulty in allowing mods to use this to communicate with users where necessary.

This would also give moderators the option of deleting certain duplicates to tidy up the site.

To ensure users know why their post has been rejected and what they can do to re-post in accordance with the moderation policy. And to prevent resentment building up against moderators which is simply based on a lack of communication.