FYI, I just enabled the “mailing list mode” feature for Discourse here.
If you visit your profile you will see:
By ticking automatically receive an email every time a post is made on the forum you are option to have the volume set to 11.
You will get every post made on the site in your mailbox.
Also, we respect your muting preferences, so if you mute a topic or category it will be excluded, something mailing lists don’t do. So take that mailing lists