Periodic Opt In

Has anyone done something like a “periodic” opt in?

The issue I have it that people subscribe to the list, ignore it for a few months, and then mark it as spam.

What I’d like to do is, say every six months, send them a notice that they need to opt in again if they want to stay on the list. Wondering if there is a not-too-difficult way to do this?

I have not done this, but a periodic opt in is of interest to me too.

Have you given any thought to it. All I can come up with is: Start an automation when people subscribe. Then when it times out, take them off the list and send them a note with a link to re-join. That sounds a little bit … hokey?