[Plugin: MailPress] Only WP users can subscrive?

Hi,

First of all… congrats on this excellent plug-in!

I have a doubt.
I have a news website, with a newsletter service. The service is available for non WP users. Now i’m changing all to Mailpress but an anonymous user don’t have access to the subscription form, subscription setting and he can see the emails on the browser.

Is the Mailpress only available if you are already register to the website?

Thanks