What is the best way to get measurable ROI from social marketing?

Building a social media community is best for increasing awareness for your company from people who are somewhat interested in what you offer. Once you have a large captive audience, generally the tactic is to encourage some level of action or activity within the group. This could be in the form of sharing your company message with their friends to grow the community, taking orders through an eCommerce store integrated right into your profile page, offering helpful info that leads to a sales call or promoting offers that funnel people into your website landing page.