Participate: Please participate in the shared learning environment. Avoid lurking in the cyberspace background. It is not enough to login and read the discussion thread of others. For the maximum benefit, everyone is intended to contribute.
Report Glitches: Discussion forums are electronic. They break. If for any reason you experience difficulty participating, please call, email, or otherwise inform your instructor of the issue so that it can be corrected as soon as possible.
Help Others: When you have more experience with online discussion forums than the person next to you, please give them a hand. Show your fellow classmates a good example, and they appreciate it!
Be Patient: Please read everything in the discussion thread before replying. This will help you avoid repeating something someone else has already contributed. Acknowledge the points made with which you agree and suggest alternatives for those with which you don’t.
Be Brief: Make the effort to be clear and to articulate your point, without being preachy or pompous. Be direct. Stay on point. Don’t lose yourself, or your readers, in overly wordy sentences or paragraphs.
Use Proper Writing Style: This is a must. Write as if you were writing a term paper. Correct spelling, grammatical construction and sentence structure are expected in every other writing activity associated with scholarship and academic engagement. Online discussions are no different.
Cite Your Sources: Another big must! If your contribution to the conversation includes the intellectual property (authored material) of others, e.g., books, newspaper, magazine, or journal articles—online or in print—give the proper attribution.
Emoticons and Texting: Social networking and text messaging has spawned a body of linguistic shortcuts that are not part of the academic dialogue. Please refrain from :-) faces and c u l8r’s.
Respect Diversity: Be sensitive to the ethnically rich and diverse, multi-cultural community in which we are participating. Please avoid any language that is—or that could be construed to be—offensive toward others. Racist, sexist, and heterosexist comments are unacceptable, as are derogatory and/or sarcastic comments and jokes directed at religious beliefs, disabilities, and age.
No YELLING! Step carefully. Beware the electronic footprint you leave behind. Using bold upper-case letters is bad form. It is the equivalent of stomping around and yelling at somebody (NOT TO MENTION BEING HARD ON THE EYE).
No Flaming! Criticism must be constructive, well-meaning, and well-articulated. Please, no tantrums. Rants directed at any other contributor are simply unacceptable and will not be tolerated. The same goes for profanity. The academic environment expects higher-order language.
Lastly, Remember: You Can't Un-Ring the Bell. Language is your only tool in an online environment. Be mindful. How others perceive you will be largely—as always—up to you. Once you've hit the send button, you've rung the bell.
Review your written posts and responses to ensure that you’ve conveyed exactly what you intended. This is an excellent opportunity to practice your proofreading, revision, and rewriting skills—valuable assets in the professional world for which you are now preparing.
Polish your Presentation. Read your post out loud before hitting the send button. This will tell you a lot about whether your grammar and sentence structure are correct, your tone is appropriate, and your contribution clear or not.
Borrowed from: http://teaching.colostate.edu/tips/tip.cfm?tipid=128