GroupServer is a Web-based mailing list manager designed for large sites. It provides email interaction like a traditional mailing list manager but also supports reading, searching, and posting of messages and files via the Web. Users have forum-style profiles, and can manage their email addresses and other settings using the same Web interface. It has supports features such as Atom feeds, a basic CMS, statistics, multiple verified addresses per user, and bounce detection, and is able to be heavily customized.
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.