Stephanie told me about this collection of 11 case studies that cover how companies in different industries tracked the ROI or results in their social media campaigns. Examples include consumer retail, enterprise, rock concerts, automobile, and so on. They measured their campaigns in social media and public relations (PR). The document includes names of tools and how they did this. See Social Media ROI Success Stories at MarketingProfs.com (I am not affiliated with them. We subscribe to their service.)