Red card/yellow card system for mods. Yellow for minor infractions, Red for major infractions or accumulation of Yellows. Red = suspension.
You can work out the details, but change the moderation to a system modeled on soccer & rugby:
- Issue yellow cards to posters who break minor rules, or do so in a minor/questionable way
- Issue red cards for major rules violations, or for an accumulation of yellow cards
- Suspensions require a red card -- there could also be different suspension levels based on yellow card accumulation (ie. repeat offenders get more time off)
- Yellow card accumulations could be shown in the users profile, or recent yellow cards could even be shown next to their names on the message board
- Yellow cards would "roll off" after some predetermined period of time -- maybe 6 months or a year.