We had a board like this on the forum I used to gMod. Basically, our ground rules were along these lines (I'm typing from memory):
- Disagreement and debate is allowed on threads in this forum, as are topics about sensitive or divisive issues, but be mindful and respectful of the opinions of others.
- Attacking another member's opinion by being verbally aggressive or insulting is not allowed and will result in the moderation or removal of the offending post.
- Topics must allow for both sides of an argument: eg. A topic about religion. "Talk about why you are or are not religious, and what, if anything, religion means to you" as a premise is acceptable; "Talk about why you hate religion" as a premise is obviously not acceptable.
- Mods reserve the right to temporarily freeze or outright lock a topic if they feel it is getting out of hand. PM a mod if you believe a topic is getting out of had - do not micro-mod the thread yourself. Topic starters may request their own topic to be locked; a mod will review the request and use their discretion in complying.
- Posters who repeatedly display aggressive or rude posting in debate topics will be warned and will be banned from the Debate subforum if behaviour continues.
- And the golden rule: Be sensible. Does your post add something to the discussion, rather than simply rehashing an existing post? Is your post polite and respectful even in disagreement? Have you read and considered the other posts in the thread before responding? If yes, go ahead and post! Otherwise, take a breath and step back for a few minutes before responding. It's for everyone's good!
We didn't have too much trouble as long as people read the rules (which were pinned at the top of the subforum, and the forum description had a clear "Read the rules before posting here!" note in it).