There are some basic rules behind writing rhetorically for message boards.

When writing for forums, knowing the audience is essential for writing material that either resonates or clashes with them. Subject in rhetorical argument refers to the "what" of the argument or the appropriateness of the subject being discussed. Usually, this subject encompasses a narrow range within the message board's basic topics. As stated before, it is very important to keep to the topic; meaningless divergence is not appreciated when in a heated or very involved debate. Usually, with the subject of the debate comes its purpose or its "why". The purpose of the debate is established by the creator of the thread.

Adhering to popular opinion when posting in forums is not required.  Becoming successful as a prominent advocate of the prevalent views is not difficult.  Becoming the token representative of an opposite, controversial philosophy presents challenges.  Forums are host to a variety of posters.  While there are many constructive people who respect varying opinions, there are others who also will not listen to any side other than their own. These are the same flamers and extremists who inhabit every board.