This is a plugin that adds a twitter link to comments if the comment author uses an email connected to a twitter account.

Add Twitter Link to Comments

This is a plugin that adds a twitter link to comments if the comment author uses an email connected to a twitter account.

This plugin allows you to add Twitter-like @reply links to comments, including a preview of the comment replied to. 
When clicked, those links insert the author name and a link to the comment you are replying to in the textarea, and adds a Preview of the original comment to the @Reply (on hover using javascript).
This is a MASHUP of <a href="http://www.spreeblick.com/2007/09/25/worst-code-ever/" rel="nofollow ugc">this</a> and <a href="https://wordpress.org/extend/plugins/reply-to/" rel="ugc">that</a>
<h3>From the original README (Credits)</h3>
by <a href="https://wordpress.org/extend/plugins/profile/iyus/" rel="ugc">Yus</a>
Most of the code is taken from the Custom Smilies plugin by Quang Anh Do which is released under GNU GPL : 
http://onetruebrace.com/custom-smilies
Thanks to <a href="http://blog.guillaumeringuenet.info/" rel="nofollow ugc">Guillaume Ringuenet</a> who made the arrow graphics.
I didn’t create anything new, and I do not claim so in any way. 
This plugin is just a feature I wanted and thought it could interest some other people.

@Reply \w comment preview

This plugin allows you to add Twitter-like @reply links to comments, including a preview of the comment replied to. MASHUP of this: http://www.

Add Twitter Link to Comments vs @Reply \w comment preview