How can a user subscribe to a notification E-mail

Hi,

The basic installation of Atahualpa comes with two links in the upper right corner of the screen, one reads "Posts" and the other one "Comments".
Hovering over these links read "subscribe to the post feed / comments feed". When clicked, the user is directed to a page containing the first line of the post / comment.

I would like to allow readers to receive a notification E-mail once a new article has been posted to the blog.

How is the user supposed to subscribe ?
Where can they enter their E-mail address?

~ Obi