Thank you for your review.
If you have existing users and want to subscribe them to an other list, you can:
-> do that in mass via our filters/actions interface
-> select the users you want on the users listing and click on the button "actions -> subscribe to..."
You don't have to edit each user one by one to subscribe them to your newly created list.
Not sure if it's what you were looking for... if not, please drop us an e-mail, we are always happy to receive new ideas to improve AcyMailing!