Beherit

Sends an simply email notification to the comment author, when someone replies to his comment. No configuration, support WordPress translation process.

Simple Comment Notification

Sends an simply email notification to the comment author, when someone replies to his comment.

scweber

Custom Comment Notifications allows for the comment email notifications to be customized. This way you can choose what information gets included in the e-mail and 
what information is left out. You can make the e-mails as detailed or as minimal as you desire. Through the use of some given variables, you are able to generate a 
standard e-mail template that will be dynamically generated and sent to your authors and moderators. You can specify a separate template for your authors and another 
for you moderators.
<h4>Available Variables</h4>
<ul>
<li>
Post Variables
<ul>
<li>Post ID</li>
<li>Post Title</li>
<li>Post Link</li>
<li>Post Link URL</li>
<li>Post Link to Specific Comment</li>
<li>Post Link to Comments Section</li>
</ul>
</li>
<li>
Comment Variables
<ul>
<li>Comment Author Name</li>
<li>Comment Author Email</li>
<li>Comment Author IP</li>
<li>Comment Author Domain</li>
<li>Comment Author URL</li>
<li>Comment Author ARIN Lookup</li>
<li>Comment Content</li>
<li>Comments Awaiting Moderation (Moderator Templates Only)</li>
</ul>
</li>
<li>
Moderation Variables
<ul>
<li>Delete/Trash Comment (Depends on EMPTY_TRASH_DAYS variable)</li>
<li>Delete/Trash Comment URL (Depends on EMPTY_TRASH_DAYS variable)</li>
<li>Approve Comment (Moderator Templates Only)</li>
<li>Approve Comment URL (Moderator Templates Only)</li>
<li>Spam Comment</li>
<li>Spam Comment URL </li>
<li>Moderation Panel Link (Moderator Templates Only)</li>
<li>Moderation Panel Link URL (Moderator Templates Only)</li>
</ul>
</li>
<li>
Site Variables
<ul>
<li>Site Link</li>
<li>Site Link URL</li>
<li>Blog Name</li>
</ul>
</li>
</ul>
<h4>Planned Updates</h4>
<ul>
<li>I plan on adding the following features shortly
<ul>
<li>Ability to specify additional recipients of the e-mails on a per template basis</li>
<li>This will allow for only the administrators to receive the moderation e-mails. Or if you have multiple moderators, it will allow each moderator to receive an e-mail</li>
<li>The additional users will be required to have an account on your site</li>
</ul>
</li>
</ul>

Custom Comment Notifications

Allow for the comment email notifications to be completely customized.

Simple Comment Notification vs Custom Comment Notifications