Your site comes with an automatic Email Subscriber field for people who’d like to be notified in case of news. You can also collect and export the inscribers, and I can recommend the use of the free service MailChimp for your newsletters.
Your inscribers will be added to your database, and can be retrieved under Email Subscriber – Subscribers(1).
You can see the subscribers all in a list(2), and can view alphabatically. You can export all addresses by hitting the Export Email button (3), and save the CSV list (will open with excel or notepad) on your PC.