The post was specifically about mailing lists as opposed to things like forums. I would love to find out about high-signal tech mailing groups. Even if they're

The post was specifically about mailing lists as opposed to things like forums. I would love to find out about high-signal tech mailing groups. Even if they're niche tech or non-software or specific language or if I need to translate them. Bonus points if they're not currently perceived as bleeding edge getting all the attention.