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.

Binesh Dobhal

go social plugin displays the social media sharing / bookmarking icons for your blog posts . It has buttons for Facebook , Digg, Google Buzz, Twitter & more to be added soon, It also displays number of likes and shares for twitter and facebook in a very neat and clean compact web 2.0 way .

go Social

Enables you to display the social media icons using direct twitter/facebook/buzz/digg  api for every post

Share Rail vs go Social