Forums are useful places for receiving information, discussing topics with peers and for asking questions relating to your course. As with any form of communication, written, spoken or otherwise, it is important that you show respect to those you are conversing with. Also remember that it is more difficult to 'take something back' in written communication. Contributions are in the public domain and 'committed to posterity'. Moodle forum posts will not be made available outside the institution however. So you should not flinch from being honest, controversial and passionate, but keep your comments on topic and avoid making personal remarks.