Working with mailing lists involves several e-mail addresses. Administrative requests, such as a request to be added to the list, dropped from the list, or asking for an index of messages that have been sent to the list, are sent to the list's administrative address. There may be a person on the other end of this address, but most often administrative requests are received and interpreted by mailing list management software. The other address is for the mailing list itself. This is the address to which messages are sent for dissemination to the entire mailing list.
Subscribers can send a reply either directly to the author of the message, or to the entire list.
In the example below, John Smith is asking the recipients of the PACS-L mailing list to fill out his questionnaire. Note the request to send responses directly to him. Some lists are moderated. This means that each message is reviewed by a human to ensure that it is appropriate and in keeping with the purposes of the list before it is redistributed to the list's subscribers. Some lists are restricted - subscriptions to the list are not available to the public.