Importing Users from a List
In Settings > Postmatic you'll find a tab named Send Invitations. Next to Who should we send this invite to? select A list of email addresses.
In the box, you can paste in a list of email addresses to send invites to. This is a good solution if you are importing users from another subscription system.
The deal is that all Postmatic subscribers have to opt-in. We are very serious about not building a nice tool for spammers and if you think for a minute about just how nice Postmatic could be for them you'll quickly understand our caution. Email is forever. You can't unpublish an email comment. It's already been sent to all of your friends. And your grandma. Just imagine.