Mailman

Mailman is GNU's popular mailing list software.

Mailman lists are easy to archive: they offer the whole archive in a single mbox file; sometimes you need to authenticate in order to access it. Otherwise, an alternative to downloading pipermail's HTML archives is to download the gzip archives, from which you can assemble an almost-copy of the original mbox. Wikistats' list archive downloader is a script to do so. In addition [[1]] supports downloading pipermail archives and converting them to other formats.