Try to get the most appropriate audience for your message, not the widest. Post relevant information and be brief. The longer your article, the fewer people will bother to read it. The subject line should be descriptive, enabling a person with limited time to decide whether or not to read your article. Marketing hype will be flamed immediately, thus keep advertising to a minimum.
Alternative groups offer a forum for discussion and alternative ways of looking at issues.
Take a break before posting something in anger or that might hurt others. Never forget that on the other side of the computer is a human being. Just before you post your article, re-read it. People do not appreciate seeing lengthy signatures, because they use up limited bandwidth and increase communications costs.