The Internet has made it possible for people from all over the world to share information and opinions. In theory, Internet forums provide an opportunity for true dialectic. In dialectic, people pool their knowledge and correct each other's errors in reasoning in a shared effort to find truth. Unfortunately, many participants view Internet discussions as an opportunity to vie for some sort of pointless social dominance. As a result, Internet discussions too often descend into "flame wars." To encourage true dialectic in your Internet forum, you must douse the flames. To do that, you must moderate the comments.
Unfortunately, few people have had any real training in how to moderate a discussion. Many people in the United States were brought up with the belief that it is impolite to talk about politics or religion. The supposed purpose of such a rule is to prevent people from engaging in pointless fights; yet in practice, that rule tends to derail democracy. You cannot have rule by the people unless a critical mass of the people learn to follow the rules of civility, which are the rules for discussing sensitive topics in public. If you want to maintain civility in your Internet forum, you must spell out and enforce those rules.
The citizens of ancient Athens developed a curriculum for teaching civility. This curriculum included training in grammar, logic, and rhetoric (the trivium) as well as mathematics, geometry, music, and astronomy (the quadrivium). The Romans called these studies the liberal arts because they were considered to be appropriate for freeborn men, as opposed to slaves. Tragically, our educators in the "Land of the Free" have been suppressing the teaching of grammar for the past half century. Yet unless you understand some basic grammatical principles, you cannot begin to study logic. Unless you can apply the basic principles of logic, you cannot even begin to study rhetoric. Thus, you will likely be irrational and unreasonable. Our political discussions in the United States today are ugly and unproductive because few of us have been schooled in these basic disciplines.
Our public schools have also done a poor job of dealing with bullying. As a result, many people have never learned that lying and personal attacks are morally wrong. They have also never learned that ad hominem arguments, which are basically a form of name-calling, generate far more heat than light. If you allow this kind of behavior in your Internet forum, the bad discourse will drive out the good, just as bad money drives good money out of circulation (Gresham's Law).
There are two challenges to moderating an Internet forum. One is simply finding the time to do it. The second is figuring out how to do it. If the purpose of the Internet forum is to promote productive discussions, you don't want to suppress inconvenient truth. Instead, you want to teach people how to participate meaningfully in real dialectic.
To have a productive dialectic, you must allow people to present reliable evidence and to make reasonable critiques of that evidence. Any statements of fact backed up by citations of a credible source should always be welcome, even if those facts challenge your beliefs. In contrast, lies and personal attacks should be deleted. But how can you tell whether a statement of fact is reliable, and whether a critique is reasonable? Fortunately, the classical liberal arts were developed to help you make those decisions. An understanding of grammar helps you understand the meaning of sentences. The study of logic helps you sort out valid and strong arguments from misleading nonsense. A study of rhetoric helps you understand the real significance of reputation and the proper role of emotion in decision making. Once you have mastered the basic principles of these three classical liberal arts, you will be well equipped to enforce civility in your forum.
To be fair, you should clearly spell out the rules of your forum. Comments that are clearly false or illogical (as opposed to being contrary to what you wish to be true) or that are defamatory should be deleted immediately. People who violate the rules should be gently corrected. People who persist in bad behavior should be suspended, at least temporarily.