Write for your audience. Use language, references, and subjects that the readers of the list will understand. But sometimes people want to know the contributor's organization, title, or even a telephone number, fax number, or postal address. Make up a signature block that contains appropriate contact information and append it to messages sent to mailing lists. But keep it short.
Nobody wants to read a full-page signature block.
Some people write long messages in an effort to avoid being misunderstood. Edit with an eye toward brevity. Cut every word that adds nothing to the meaning of the message. Organize the message. For those rare messages that are quite lengthy, include an overview and a summary.