MailChimp is an external tool that can be synced with your GSEcommerce website to help manage the sending of newsletters by compiling information based on your customers' activities on your site. You will need to sign up for a MailChimp account.
Connecting to MailChimp through your GSEcommerce site is fairly simple. Navigate to System > Configuration. Using the navigation column on the left, scroll down to SiteBiz > MailChimp Configuration.
From here you will be able to enable MailChimp and input your API Key. MailChimp will generate your API Key through your MailChimp account by navigating to Extras > API Keys > Create API Key.
Your API Key will then be generated:
Copy and paste the API Key into the API Key field in your system configuration.