To find publishers that work in a special vertical, e.g. in Social Search, go to Account Management > Publisher Management > Find Publishers. This will take you to the Publisher Directory. Click on the Search tab at the top of the Publisher Directory. In the Refine Search box on the left-hand side of the directory, you are now displayed all publisher verticals related to search activities. Select Social Search to display a list of publishers whose business models are focused on social search activities.