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.

benjiballin

The Twiogle Twitter commenter plugin pulls in comments from Twitter to your own blog posts. 
This plugin will look at every tag in your post and try to pull tweets from twitter based off of your tags and post that tweet as a comment on your post. 
Be sure to tag your posts with good tags, do not tag your posts with an unfamiliar word or it may not pull any comments
<ul>
<li>gets your archived posts and pages re-indexed because content will be ever changing</li>
<li>manages the organic page growth of your autoblogs</li>
<li>injects targeted (based on your tags) content and keywords into your posts</li>
<li>encourages real readers to add their own comments, no one wants to be the first one to comment</li>
<li>removes the zero comment footprint common to most blogs</li>
</ul>

Twiogle Twitter Commenter

The Twiogle Twitter commenter plugin pulls in comments from Twitter to your own blog posts.

CommentTweets vs Twiogle Twitter Commenter