Mailman Email list that I didn't sign up for

[djmatt]

I got the monthly reminder from a Mailman email list that I never would have signed up for. Since mailman is not monitored, I am guessing that if I "unsubscribe" the spammer running that site will know that email is valid and will sell it. Is this a reasonable conclusion?

Mailman can be configured to send an email listing the address that unsubscribes.

And also, since Mailman is self run, I'm guessing there is no way to report this person for singing me up?

[Professional Dude]

There is a possibility that once you unsubscribe, you might start receiving more emails.
My suggestion would be to simply ignore these emails/mark them as spam or simply put a block on the domain name where you are receiving these emails from.