This page describes specifically the way the mailing lists run by 4QD operate. However most mailing lists work on very similar lines with only minor differences, so it may be a helpful introduction to other mailing lists.
Mailing lists are half way between newsgroups and email.
All you have to do is log on to the n.g. and pick up the postings. Email is a private system whereby you, at your computer, send an electronic mail to another person at another computer. Of course, you can send umpteen copies of the same email to umpteen different persons. That, of course, is the method used by spammers - when it is most popular. But it's quite acceptable amongst a few individuals.