The list is uncensored, i.e. nobody screens the messages before they are posted. The machine delivers them automatically. Use lines shorter than 80 characters since many mailers truncate longer lines. Remember that what you post will be received by many people in many countries. However, do not feel overly paralyzed about this.
Communication is a two-way street.
Be concise though. Not everybody has superworkstations connected to a high-speed network. However, do not be overly concise. Also, summarize to the list the responses you got. We want to know what you know.