I have often wondered what a bitcoin mailing list relay would look like. Perhaps ASCII only. Integrate with a mail server or email service. Whitelisted accounts. Mods can delete notes, lock threads, etc. It only impacts the bitcoin dev relay. If you want to reply to a post on a different relay no one can stop you. Client settings control which relays to look at.

I've imagined similar. A plug and play mailing list relay anyone can run, but centrally gated. Almost like a relay federation. Whitelisted npubs. Note sharing. Of course with nostr anyone could reply to the notes on their own relay, but one could filter to viewing the gated relay to eliminate Sybil.

Why does it need to support email signup? I don't think the mailing list actually wants to use email as their discussion interface.

I has the least friction of entry. Everybody has an email client. Few have nostr clients. It is integrated in countless hacker tools and familiar to everybody.