My site builder system comes complete with various features to incorporate email marketing. I have the Join Email List page template where users can opt into your email list. There's aslo various other forms, including the shopping cart, that are designed to retain user's submitted email addresses into your database.
These email addresses can be sorted and split into any number of email lists you wish to generate. Furthermore, I have tools for you to import or export those email lists.
The site builder's backend control panel has a bulk emailer where you can compose a message and send it any list you create, or everyone on your list.