Social Share Buttons
This is a free service that generates a social share buttons that allows your visitors to post links to your articles in social media (bookmarks, social networks).
Social share buttons is a free services allows you to create nice widgets sharing for Facebook, Twitter, Google Plus and more.

Horizontal Share Button
You can position horizontal share buttons in a "floating bar" that is display the bottom of the user's screen.

Vertical Share Button
Position floating vertical share buttons that are fixed in a sidebar the far left side of the user's screen.