pop3ml is a program to manage mailing lists and newsletters without a local SMTP server. It requires only a simple POP3 email account. It's highly configurable by users. You can subscribe or unsubscribe simply with email messages. There is optional subscription and unsubscription confirmation, subscription moderation, message moderation, digest message mode, parent/children list management, mail scheduling to postpone or repeat a message, a mail filter (with a procmail-like syntax), a message queue for unsent messages, message size check, a command to retrieve messages, bounce detection, message header management, black/white/allow/deny lists, and other functions. There is also a program to test list settings without sending any messages and another program to view and search through stored messages. You can configure it with programs like phpMyAdmin.
Listserv is software for managing mailing lists: creating lists, distributing emails over the list, adding new subscribers, and adjusting settings. It can be operated via a Web interface, by sending email commands, or via TCP. liblistserv is the glue between listserv and your C program for manipulating or querying a mailing list. By calling the provided functions, your program does not need to parse the results. Liblistserv is a reentrant library, written in C, meant for communication over TCP with a running Listserv instance.
mailing-lists-sieve is a utility to generate Sieve scripts (RFC 5228) for listserv mailing lists and upload them with the ManageSieve (RFC5804) protocol. The program can be extended to generate scripts for other mailing list managers or upload them by other means. mailing-lists-sieve can integrate into listserv and upload the scripts for the mailing lists when a new subscriber is added or removed from the list.