Such entries are as useful as no entries at all. If you reply to a message but change the subject either change the subject field entry or start a new message altogether. Do everyone a favor and include only enough of the original message to provide a context or reminder and no more. Many listowners will simply remove subscribers who repeatedly breach this practice. Most mail programs have a setting that lets you choose a visual reminder that identifies the quoted text.
Collegial discourse is possible even for contentious topics.
Phone and fax numbers, additional e-mail and internet addresses, including home pages are usually listed to offer alternate means of contact. Signatures should be short. As a rule, anything over eight lines is frowned on. Because on lists, they add to the bandwidth. In der Kuerze liegt die Wuerze.