Great idea, but I'd rebrand due to the main mailing list software being called Mailman already.

(the "mailman" part is probably the wrong thing for branding, anyway -- I'd pick branding focused on the sponsor/trust/endorsement/patron aspect, so you can extend to other channels like video. You should decide if you're selling single branded links or (limited duration?) sponsorship.

If it's a sponsorship marketplace, the value is a lot higher to both sides -- if there were a great "devops security bulletins" newsletter or alert list, it would easily be worth $10-20k/mo for a remediation vendor, platform vendor, or specialist recruiter to sponsor it, and you'd get a larger amount of money than selling a bunch of $100 links. There are probably thousands of valuable niches out there.)