leo108

When someone reply a comment, the person who receive this reply will receive a mail. 
当有人回复评论时，被回复的人会收到一封提醒邮件。

Comment Reply Notifier

When someone reply a comment,the person who receive the reply will receive a mail 有人回复评论时，被回复的人会收到一封提醒邮件

yakuphan

Comment Approved Notifier sends an e-mail to your commenters when you approve their comments. It is a very simple plugin. There are no settings, options. It starts to work when you activate it.
<h4>Read Please</h4>
If you upgraded to WP 2.7 or WP 2.8, please, update v1.1 to v2.1 
It requires at least 2.7. If you use WP 2.6.5, please use version 1.1
Thanks!

Comment Approved Notifier

https://wordpress.org/plugins/comment-approved-notifier-extended/
Updated version of this plugin. forked.

Updated

The plugin sends an e-mail to your commenters when you approve their comments.

Comment Reply Notifier vs Comment Approved Notifier