denishua

When a reply is made to a comment the user has left on the blog, an e-mail shall be sent to the user to notify him of the reply. This will allow the users to follow up the comment and expand the conversation if desired. 
Detail information: http://theme10.com/comment-reply-notification/
中文介绍： http://fairyfish.net/2008/11/03/comment-reply-notification/

Comment Reply Notification

When a reply is made to a comment the user has left on the blog, an e-mail shall be sent to the user to notify him of the reply.

aviplugins.com

Use this plugin to create your very own customer support system. Let customers of your site to generate a support ticket whenever they require assistance from you, and you will be able to solve their issues by posting replies to the tickets. The customers will get email notifications when you post a reply message to the ticket.
<ul>
<li>Registered Users / Customers can create support tickets.</li>
<li>Customers can search tickets from tickets list.</li>
<li>Admin can reply on support tickets from admin panel.</li>
<li>Files can be attached to the reply messages. Supported files that can be uploaded are jpg, jpeg, png, gif, doc, docx, pdf, zip ( Multiple files can be attached in the <a href="https://www.aviplugins.com/wp-support-pro/" rel="nofollow ugc">PRO</a> version with option to select which type of files can be uploaded. )</li>
<li>Ticket can be marked as Open / Closed / Resolved from admin panel. If a customer post a reply in the Resolved ticket the status of the ticket will be changed to Open.</li>
</ul>
<h4>Usage Shortcodes</h4>
<ul>
<li>[create_support] to display cretate new suppor ticket form.</li>
<li>[ticket] to display tickets created by logged in user.</li>
<li>[ticket_search] to display ticket search form.</li>
</ul>
<h4>WP Support (PRO)</h4>
There is a PRO version of this plugin that supports additional features. You can get it <a href="https://www.aviplugins.com/wp-support-pro/" rel="nofollow ugc">here</a> in USD 2.00
<ul>
<li>Administrators can post replies by logging in to admin panel. Additionally a new user role Agent will be created. Administraton can assign this role to the support agents so that they can login to the admin panel and reply to the support tickets. Agents will have limited access (Only Support Ticket Section) of the admin panel.</li>
<li>Multiple files can be attached with new tickets and ticket replies.</li>
<li>Create Custom Fields in the ticket form.</li>
<li>Create Support Ticket (Widget).</li>
<li>Support Ticket List (Widget). To list recent/ specific tickets in the widget area.</li>
<li>Additional file types are supported in the PRO version. Set supported file types from admin panel.</li>
<li>Manage email contents from admin panel. Emails that are fired when a new ticket is created or admin posts a reply.</li>
<li>Option to list all support tickets submitted by users. So that visitors can view tickets and replies.</li>
<li>Set custom name for the administrator.</li>
<li>Advanced ticket search.</li>
</ul>
<blockquote>
Post your plugin related queries at <a href="https://www.aviplugins.com/support.php" rel="nofollow ugc">https://www.aviplugins.com/support.php</a>
</blockquote>

WP Support Ticket

This is a easy to use user support plugin. :)



User Support Solution.

This is best and very simple plugin for support management. thanks.

AWESOMEEEE!!!!

User support plugin. Registered users will be able to create/ reply support tickets. Admin can reply on the tickets from admin panel.

Comment Reply Notification vs WP Support Ticket