Social reports focus on only social traffic from social networks, there are 3 reports available in the Social Traffic Section:
The Social Overview reports show you the high level information about your website's social traffic over time.
Social Networks report don't only show you your social traffic but also grouped them by different social networks, you can visualize these data with a trend chart or a pie chart.
Social Landing Pages
Social Landing Pages report shows you all the social traffic data grouped by landing pages, you can visualize your landing page traffic with the pie chart to see the distribution of landing page traffic across your site.