As an example our PRO hosting accounts do have a subscribe to a mailing list function which takes care of all the scripting for you. You create a mailing list, it supplies you with a code snippet which you can insert via the insert HTML markup function.
This code adds a subscribe/unsubscribe button for your web page whereby the subscriber can add or remove their email address the mailing list. They also get an email confirmation to approve the subscription all this helps you comply with anti spam laws. The email gets added to a list server side where you can manage. You compose plain or HTML email to send to the list directly from the hosting control panel.