Some mail system managers use info-servers to maintain mail lists. Mail lists are ways of sending a message at one go to groups of people possessed of a common interest or purpose. They resemble, but are completely different in implementation from Bulletin Boards, of which more below. Mail lists are very useful when used discriminatingly. On the other hand, because it is as easy to send to a list as to an individual, sometimes, users propagate junk mail to large groups of people. The most common typical piece of junk mail is to do with list management (e.g. ``please add me to this list'' or ``please remove me from this list'', which should be directed to list managers, usually as `` listname -request''), but other human errors include sending irrelevant or offensive information. Some (some might say paranoid) sites restrict list usage strictly to internal inter-office memos.
List maintenance is carried out in a centralised way. At a mail-system site, a user creates a list name and sets up the contents, the list of each members personal e-mail address (typically by putting them in a file). Then users can send to the list by sending to the list-name at the central server machine.
There are a couple of other features of lists worth mentioning: Lists can be moderated, where material is ``censored'' by a list maintainer or moderator before being circulated. Many lists also provide digests terms-of-reference, FAQs (Frequently Asked Questions) and so forth periodically to the list, to pre-empt repetition of discussions, and to reduce traffic.