According to the U.S. National Library of Medicine, in Bethesda, MD, the following (excerpts) define "netiquette":

DO keep postings on the specified discussion topics of that particular list.

DO search the list archives prior to posting a question to prevent repeat questions.

DO be careful when using humor in your messages.

DO NOT be critical of other's queries posted to the list. Send a private message and gently make suggestions for future postings, if appropriate.

DO NOT post messages containing any defamatory, abusive, profane, or offensive language, or post illegal material.

DO NOT "flame" individuals on the list. Conflict should be resolved in personal e-mails.

DO NOT send messages with little or no meaningful content, such as "I agree!", to the entire list. Send this type of reply to the sender of the original posting.

While we ain't got no steenkin' roolz on this board, and while I have violated most if not all of these suggestions at one time or other, they do make a certain amount of good sense, as a guide to self-restraint.