Goran Petrovic

This utility plugin allow you to bookmark your site in admin bar.
This plugin is very useful if you have several, local or online, WordPress instalations.You can set up all sites admin bar, from one point.
So, you can jump fast from WP admin to WP admin.
Features
<ul>
<li>Fast jump from WP to WP </li>
<li>Global register sites</li>
</ul>

WP Jump

oneline

A Simple plugin which adds a widget to your wordpress admin widget area which you can then assign to the side bar etc… features are as follows:
Allows you to set your user / social ID’s 
Allows you to switch from icons or text links 
Allows you to turn social button / links on or off
Supported Social Sites:
Facebook 
Twitter 
Linkedin 
RSS

Easy Social Share

A Simple plugin which adds a widget to your wordpress admin widget area which you can then assign to the side bar etc...

WP Jump vs Easy Social Share