JJ Social Slider is a free module for Joomla. It work on all latest Joomla releases on either left or right hand side at fixed position. JJ Social Slider is developed by JoomJunk.
I've decided to write review of this superb module, as many times, I was asked on Facebook, Twitter, Google Plus and LinkedIn, what I am using at WebmaisterPro.
This social slider use jQuery or CSS3 animations and on hover images pop-up, bringing impressive effect and high visibility of social media profiles on pages selected. This extension is well maintained and there are regular updates.
Quite easy to find similar component in WordPress, but I think JJ Social Slider is unique extension for Joomla, that every website should have installed. You can see the demo on right hand side at WebmaisterPro.