The exact format may be a little different from one list server to another, so pay attention. A list server is an automated program. It does not truly read your message, so give it what it needs and only what it needs. If you add extra words you will confuse the machine and make its head hurt, so please send notes separately either to the list itself, or the listowner, but not to the list server. Send the right commands and it works just fine.
Some lists are very busy.
To be able to both enjoy the lists and still find personal mail many people subscribe to one of the free email services for their email discussion lists. A listserver is not Usenet. Usenet is an entirely different system than the listserver. Although some people receive their usenet postings through their e-mail, most people do not. You should not presume that the way you experience a newsgroup is the same for everyone, or even for most people.