Mailing List Use – Replying
Basic replying advice is to reply just to the author of a posting unless the discussion is of general interest.
Before you reply to a mailing list posting, consider whether or not the reply should be sent to the entire list or just directly to the author. Often the reply is best sent to the author, because only they will be interested in the reply. On the other hand, if your reply contains information of interest to everyone on the list, then you should send it back to the list server for distribution to everyone.
You should reply to both the author and the entire list if (a) your reply is relevant to the list, and (b) you want to make sure the author will notice it in case they don’t review the list postings regularly or thoroughly.
Email from mailing lists often comes from a standard mailing list email address, so there is no way to tell who sent a message from your email inbox without opening it. As an aid to others to help them know who sent each posting on these kinds of lists, it is sometimes considered good form to append the subject of a reply with a slash followed by your name, such as the following:
Re: Zebras are horses! / JSmith
This is a big help to people who want to read (or avoid) certain people’s postings, and helps folks to find additions to discussion threads by people known to have good postings, or to avoid replies by people known to have bad postings. (This advice also applies to replying to Usenet newsgroups messages.)