When a reply is made to a comment, a twitter notification (@twittername) will be sent to the original comment author to notify him/her of the reply. The notification will be sent from your Twitteraccount. 
This will allow the users to follow up on the comment and expand the conversation if desired.

CommentTweets

When a reply is made to a comment, a twitter notification (@twittername) will be sent to the original comment author to notify him/her of the reply.

This plugin allows you to add Twitter-like @reply links to comments. 
When clicked, those links insert the author name and a link to the comment you are replying to in the textarea.
Most of the code is taken from the Custom Smilies plugin by Quang Anh Do which is released under GNU GPL : 
https://wordpress.org/extend/plugins/custom-smilies/
Thanks to Guillaume Ringuenet for 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 judging by the number of downloads I guess I wasn’t the only one. 😉

@ Reply

This plugin allows you to add Twitter-like @reply links to comments.

CommentTweets vs @ Reply