wp.insider

smp7

This addon allows you to specify a MailChimp list name for each of your access levels. When members join your site, they get signed up to the specified MailChimp list.
This addon requires the <a href="https://wordpress.org/plugins/simple-membership/" rel="ugc">simple membership plugin</a>.
After you install this addon, edit your membership level and specify the mailchimp list name. Then go to the MailChimp settings interface and specify your API Key.
Read the following page for step by step usage documentation: 
https://simple-membership-plugin.com/signup-members-mailchimp-list/

Simple Membership MailChimp Integration

An addon for the simple membership plugin to signup members to your MailChimp list

frenchsquared

Comment-Emailer allows you to customize the email wordpress automatically 
sends when a new comment, pingback or trackback has been approved. 
With Commented-Emailer you can change the sending email address, message body, 
and enable or disable all of the default options such as including the authors 
name, ipaddress, website, comment or reply to address.
After installation you will have a new tab under settings that 
will give you access to change just about every access of your 
auto generated emails. Just make sure you enable Commented-Emailer

Comment-Emailer

Comment-Emailer allows you to customize the email wordpress automatically sends when a new comment, pingback or trackback has been approved.

Simple Membership MailChimp Integration vs Comment-Emailer