Box with social buttons is the easiest way to share your links with friends, using popular social services like Facebook, Twitter and others. Sure your visitors have friends with similar interests who will also be happy to visit your website. This is the web version of the Word-of-mouth marketing which is really difficult to overestimate.
To manage it open section “Social” on the theme settings page in your dashboard. There you can see a list of available social services, which provide social buttons. Just click the needed service in this list to add it to the “Social Buttons” on your website.