n. (often shortened in context to 'list') 1. An email address that is an alias (or macro, though that word is never used in this connection) for many other email addresses. Some mailing lists are simple 'reflectors', redirecting mail sent to them to the list of recipients. Others are filtered by humans or programs of varying degrees of sophistication; lists filtered by humans are said to be 'moderated'.
2. The people who receive your email when you send it to such an address.
Mailing lists are one of the primary forms of hacker interaction, along with USENET. They predate USENET, having originated with the first UUCP and ARPANET connections. They are often used for private information-sharing on topics that would be too specialized for or inappropriate to public USENET groups. Though some of these maintain purely technical content (such as the Internet Engineering Task Force mailing list), others (like the 'sf-lovers' list maintained for many years by Saul Jaffe) are recreational, and others are purely social. Perhaps the most infamous of the social lists was the eccentric bandykin distribution; its latter-day progeny, lectroids and tanstaafl, still include a number of the oddest and most interesting people in hackerdom.
Mailing lists are easy to create and (unlike USENET) don't tie up a significant amount of machine resources. Thus, they are often created temporarily by working groups, the members of which can then collaborate on a project without ever needing to meet face-to-face. Much of the material in this book was criticized and polished on just such a mailing list (called 'jargon-friends'), which included all the co-authors of Steele-1983.