baxeico

This plugin allows to mention WordPress users in a comment by writing usernames preceded by a character (default @), e.g. @guguweb. 
The mentioned users will receive a notification email with a link to the relevant post.
The mention character (default @) can be customized by a filter hook: <code>cum-mention-char</code>. Put the following code in your theme <code>functions.php</code> file:
<pre><code>add_filter( 'cum-mention-char', 'cum_custom_char' );
function cum_custom_char( $content ) {
 return '+';
}
</code></pre>
And the mention character will be +, so you can mention with +guguweb.
This plugin was inspired by <a href="https://wordpress.org/plugins/mention-comments-authors/" rel="ugc">Mention comment’s Authors by Wabeo</a>. Many thanks to the <a href="http://wabeo.fr" rel="nofollow ugc">author</a>!

Comments Users Mentions

Allows to mention Wordpress users in a comment. The mentioned users will receive a notification email.

Raulanton

This ultra light-weight plugin send a customizable notification email to each user/author mentioned in a comment.
Mentions: A mention is an username preceded by the mention qualifier.
Username: This plugin will look for the username in display_names and logins. Multiple authors could be mentioned in a comment.
Qualifier: Can be a character but also a string. 
The default qualifier is ‘@’ to work as in Twitter, but it could be changed via admin menu to be ‘#’ or even an string like ‘Mention:’ .
Email:
The email can be customized to include or not the whole comment in wich the mention is. 
The email can be customized to add a reference to the mentioner profile at the site. 
It is also possible to define email header and footer. 
The email can include the URl to the comment in which he/she was mentioned
I18N:
This plugin is I18N (es_ES, en_US, fr_FR) 
Any help with translations will be nice!

Email Mentioned

Email Mentioned is a lightweight customizable -no coding needed- plugin to send an email to each user mentioned in comments.

Comments Users Mentions vs Email Mentioned