If you wouldn't say it face to face, don't post, text, email, tweet or IM it.
So many children and teens are having arguments online that could be easily avoided if they followed the same social code online that they do IRL (in real life). It’s been said before, but it’s worth mentioning again: without facial expression, body language and tone, words can take on a whole new meaning. The reader interprets them, often wrongly, and attributes meaning where there may be none; then they respond in kind. And so the spiral begins, often ending badly for all.