This document provides a quick introduction to calculating return on investment (ROI) for social media marketing. It explains that ROI is a business metric, not a media metric, and evaluates the impact on key metrics like loyalty, transactions, customers and revenue. The ROI equation is defined as (income - spend) * 100 / spend. The document recommends tracking metrics before and after social media activities to identify changes and figure out the ROI by applying the equation to factor in cost savings and new business generated.