There a few simple steps to implementing social share buttons with a service like ShareThis or AddThis.
In our example we'll use ShareThis.
Go to https://www.sharethis.com/platform/share-buttons/.
Choose to "Get Share Buttons" > Choose between "Inline" or "Sticky" button styles. For this example, we'll choose "Sticky".
You'll now see a range of options to configure your sharing buttons. For our example, we'll choose to display Facebook, Twitter, Email and ShareThis buttons. We'll also choose not to display the total count of shares. Once you're happy with the look click "Register & Get Code".
Once you've filled in your domain, email and password click sign up.
Now you'll be presented with the code to power your share buttons. Copy this code.
Now we want to add the buttons to our uSkinned website.
Login to the CMS > Expand Website Configuration node > Open Global Settings > Go to the tab Scripts > Paste the code you copied from ShareThis into "Header Scripts" > Click Save and Publish.
Your Social Sharing buttons will now be present and responsive on your Umbraco theme.