Bloafer

Use this plugin to apply <a href="https://wordpress.org/extend/plugins/share-rail/screenshots/" rel="ugc">floating shares</a> to your posts and pages.
This is very similar to the one found on mashable.com.

Share Rail

Use this plugin to apply floating shares to your posts and pages.

DZVO

This plugin allows you to display a buttons which shows the voting for a social news message (digg,sphinn …) on your blog post. 
You will find a collection of voting buttons for different social-news-services <a href="http://www.zauberpage.de/vote-it-liste.html" rel="nofollow ugc">here</a>.

Vote It!

Vote It! Buttons for Blogpostings. Set very simple a digg, sphinn or another social-news-button in your blogpost.

Share Rail vs Vote It!