olivierognn

With this plugin you can use the shortcode [twitter-author] to add a nice preview of the author’s twitter profile in your post. The only requirement is that the author has indicated his twitter nickname in the user management page of WordPress.

twitter-Author-follow

This plugin helps you to show the author twitter profile in your posts using the shortcode [twitter-author]

Skysa

Simply set the Twitter account you want users to follow; then, when they click the Twitter Follow button at the bottom of your site, they will start following your account on Twitter. You can optionally set to display your current followers count next to the Twitter follow button and also the language of the Twitter follow button text.
http://www.youtube.com/watch?v=Zj1uGXX2xrk&hd=1 
<a href="https://wordpress.org/extend/plugins/tags/skysa-apps" rel="ugc">More Skysa App plugins</a> -|||- <a href="https://wordpress.org/extend/plugins/skysa-official/" rel="ugc">Skysa App Bar Integration plugin</a>

Skysa Twitter Follow App

Allows your site visitors to follow your twitter account with one click, without leaving your sitet.

twitter-Author-follow vs Skysa Twitter Follow App