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.

nickgrossman

Enable commenting on your posts via Twitter.
Posts will get a “Discuss on Twitter” button, which will prompt visitors to reply to the original tweet about the post, as well as a “View Discussions” button which will link to existing tweets about the post.
Each new post will be auto-tweeted (requires the <a href="https://wordpress.org/plugins/wp-to-twitter/" rel="ugc">WP to Twitter</a> plugin and a <a href="https://developer.twitter.com/" rel="nofollow ugc">Twitter Developer account</a>).

Add Twitter Link to Comments vs Discuss on Twitter