Students are expected to contribute actively to the online classroom environment. Keep track of where you post questions to your peers, and return to see whether you sparked a conversation. When you encounter a good question, post a thoughtful and careful response. If you notice two people have posted related questions in different places, direct them to each other, and add whatever insight you can find. (The rubric for the Participation Portfolio describes many different ways that you can demonstrate online participation; I'll go into that in more detail at the right time.)
Some of your online work will appear in public spaces, where it may attract comments from diverse readers. Some of those outsiders may have no interest an open, honest discussion of differences, and some may just want to pick a fight. You won't lose points in this class just because some random person flames you, so if you encounter a post that rubs you the wrong way, give the poster the chance to explain or even retract.
Presume your peers are acting in good faith, and don't feed the trolls. Nobody ever lost respect for ignoring rudeness and taking the moral high road.