Mehdi Kabab

This plugin allows to display or retrieve comments posted by a user. In order to avoid homonyms, a user is identified by his name and email(s).
Note: Get Author’s Comments uses the function <a href="https://codex.wordpress.org/Template_Tags/wp_list_comments" rel="nofollow ugc">wp_list_comments</a> introduced by WordPress 2.7 for the (x)HTML output.
<h3>Usage</h3>
<h4>Display all comments of a specific user in the current post</h4>
<pre><code><?php
 <ol>
 <?php ppm_author_comments('piouPiouM', 'foo@example.com'); ?>
 </ol>
?>
</code></pre>
or, if piouPiouM wrote with two different emails:
<pre><code><?php
 <ol>
 <?php ppm_author_comments('piouPiouM', array('foo@example.com', 'bar@example.org')); ?>
 </ol>
?>
</code></pre>
<h4>Display all comments posted by a user</h4>
<pre><code><?php
 <ol>
 <?php ppm_author_comments('piouPiouM', 'foo@example.com', null, 'all=1'); ?>
 </ol>
?>
</code></pre>
<h4>Display comments wrote by a user in the post of ID number 9</h4>
<pre><code><?php
 <ol>
 <?php ppm_author_comments('piouPiouM', 'foo@example.com', 9); ?>
 </ol>
?>
</code></pre>
Note: If you used the tags <code>ppm_author_comments</code> or <code>ppm_get_author_comments</code> whithin <a href="https://codex.wordpress.org/The_Loop" title="The Loop « WordPress Codex" rel="nofollow ugc">The Loop</a>, the parameter <code>$postID</code> will be replaced automatically by the numeric ID of the current post.
<h4>Lastest comments ordered by post_ID</h4>
To show the last ten piouPiouM’s comments sorted by post_ID in ascending order, the following will display their comment date and excerpt:
<pre><code><?php
 $comments = ppm_get_author_comments('piouPiouM', 'foo@example.com', null, 'number=10&order=ASC&orderby=post_id');
 foreach ($comments as $comment):
?>
<cite><?php comment_author_link() ?></cite> says:
<ol>
 <li>
 Comment posted on <?php comment_date('n-j-Y'); ?>: 
 <?php comment_excerpt(); ?>
 </li>
</ol>
<?php endforeach; ?>
</code></pre>
<h4>Comments with a custom comment display</h4>
<pre><code><?php
 <ol>
 <?php ppm_author_comments('piouPiouM', 'info@example.com', null, 'callback=mytheme_comment'); ?>
 </ol>
?>
</code></pre>
See <a href="https://codex.wordpress.org/Template_Tags/wp_list_comments#Comments_Only_With_A_Custom_Comment_Display" title="Template Tags/wp list comments « WordPress Codex" rel="nofollow ugc">Comments Only With A Custom Comment Display</a> for an example of a custom callback function.
<h4>Show the total number of comments posted by a user on the site</h4>
<pre><code><?php
 get_currentuserinfo();
 $comments = ppm_get_author_comments($current_user->display_name, $current_user->user_email, null, 'all=1');
 printf('Hello ! <a href="/author/%s/">%s</a>! '
 . '[ <a href="%s" class="logout">Log Out</a> ] '
 . '%d posts and %d comments',
 $current_user->user_login,
 $current_user->display_name,
 wp_logout_url(),
 get_usernumposts($current_user->ID),
 count($comments));
?><h3>Parameters</h3>
</code></pre>
all 
(boolean) (optional) Retrieve all comments. Default to FALSE.
number 
(integer) (optional) Number of comments to return. Default to None, returns all comments.
offset 
(integer) (optional) Offset from latest comment. Default to 0.
orderby 
(string) (optional) Sort posts by one of various values (separated by space), including:
<ul>
<li><code>'comment_ID'</code> – Sort by numeric comment ID.</li>
<li><code>'content'</code> – Sort by content.</li>
<li><code>'date'</code> – Sort by creation date. (Default)</li>
<li><code>'post_ID'</code> – Sort by post ID.</li>
<li><code>'rand'</code> – Sort in random order.</li>
<li><code>'status'</code> – Sort by status.</li>
<li><code>'type'</code> – Sort by type.</li>
</ul>
order 
(string) (optional) Sort order, ascending or descending for the orderby parameter. Valid values:
<ul>
<li><code>'ASC'</code> – Ascending (lowest to highest).</li>
<li><code>'DESC'</code> – Descending (highest to lowest). (Default)</li>
</ul>
output 
(string) (optional) How you’d like the result. Only for <code>ppm_get_author_comments</code>.
<ul>
<li><code>OBJECT</code> – Returns an object. (Default)</li>
<li><code>ARRAY_A</code> – Returns an associative array of field names to values.</li>
<li><code>ARRAY_N</code> – Returns a numeric array of field values.</li>
<li><code>HTML</code> – Returns a (x)HTML version generated by <a href="https://codex.wordpress.org/Template_Tags/wp_list_comments" rel="nofollow ugc">wp_list_comments</a>.</li>
</ul>
status 
(string) (optional) The comments status. Default to hold and approve. Valid values:
<ul>
<li><code>'hold'</code> – Unapproved.</li>
<li><code>'approve'</code> – Approved.</li>
<li><code>'spam'</code> – Spam.</li>
</ul>

Get Author's Comments

Get Author's Comments displays or retrieves a list of comments posted by a user.

Newt Labs

This simple, lightweight plugin solves one particular issue. WordPress doesn’t include any alt text or a title tag when using Gravatars. This addresses that by using the comment author name for each of your comment’s Gravatars, and for any other Gravatar usage it should use the authors display name.
So if you create a post it will use your name for your Gravatars Alt text and Title tag and then for the comments it will use the commenters name for their Gravatars Alt text and Title tags.
With this plugin you can squash those pesky warnings given by SEO reporting tools that look for missing alt text and title tags.
<h3>Important Notes</h3>

Fix Gravatar Alt Text & Title Tag

Applies comment author name to Gravatar's Alt and Title tags in comments and author display name to Gravatars site-wide.

Get Author's Comments vs Fix Gravatar Alt Text & Title Tag