"An electronic mailing list or email list is a special use of email that allows for widespread distribution of information to many Internet users. It is similar to a traditional mailing list – a list of names and addresses – as might be kept by an organization for sending publications to its members or customers, but typically refers to four things:

* a list of email addresses
* the people ("subscribers") receiving mail at those addresses, thus defining a community gathered around a topic of interest.
* the publications (email messages) sent to those addresses, and
* a reflector, which is a single email address that, when designated as the recipient of a message, will send a copy of that message to all of the subscribers. "

Quoted from https://en.wikipedia.org/wiki/Electronic_mailing_list

I'm on the following lists as of yet :

Read-only
* caml-news-weekly@lists.idyll.org

Read/write
BSDs
* freebsd-stable@freebsd.org
* netbsd-users@netbsd.org
* misc@openbsd.org

Orbifx's
* community@lists.orbitalfox.eu (defunct)
* comp@lists.orbitalfox.eu (defunct)
* logarion@lists.orbitalfox.eu (defunct)

Tildeverse
* tildeteam@lists.tildeverse.org (on my team email)
* main@envs.net (on my envs mail)

I've had good experiences so far , and I learnt many things from mailing lists in general.