Mailchimp is a 3rd party service that sends email.

Why use Mailchimp?

• Delivery - Spam is a huge problem. If Gmail or Outlook suddenly sees you send out hundreds or thousands of emails - they're going to block you. It's way too suspicious. Gmail knows who Mailchimp is, know which servers they use, and they know that Mailchimp takes steps to make sure the emails are valid.
• Organization - You can create multiple lists to organize customers, contacts, warranty holders, etc.
• Analytics - How many email were delivered? How many were opened? How many people clicked on a link and returned to your website? Mailchimp can tell you all of that.
• Manage Unsubscribes - If someone unsubscribes, do it. If you forget and send them more email you're turning a potential customer to a hater. With Mailchip it quick and easy to unsubscribe.
• It's Free for small accounts - If you have less than 2,000 email subscribers, you can use MailChimp's most basic plan for free.

The CFWebstore Mailchimp API connection automatically sends your customer emails to your list at Mailchimp.

OPT-IN

• Be sure to turn on 'Subscribe Box' in Users > User Settings. You need to give your Users a chance to opt-out.
• If you want to collect email addresses from Customers during Guest checkout you can do so in Mailchimp > Mailchimp Settings