In order to target website visitors who come from specific traffic sources, you will need to create a Nugget following the steps below:
1) Create a New Nugget (or, if you want to A/B test traffic sources with the same design, clone an existing Nugget and simple Customize setup using the following steps).
2) Select Customize Setup, scroll down to Source and select Social Media. This ensures that ONLY visitors coming in from social media will be presented with this Nugget.
3) To target a specific campaign, scroll down to 'Where On Your Website' and INCLUDE the specific URL you are using on Twitter or Facebook for example.
4) Name the Nugget something which identifies the custom source inside the title ("Facebook 10% discount" or "Twitter newsletter signup").
This setup will ensure the Nugget only appears to visitors coming in through the traffic source you have selected and the Nugget will appear only for those coming into your site from the URL you have INCLUDED.