This document provides an introduction and overview of social media. It discusses the history of social media from early phone phreaking and bulletin board systems to modern platforms like Friendster and Slashdot. The benefits of social media are connecting people, recommending resources, and distributing content. Popular social media channels described include blogs, microblogs, social networking sites, wikis, and multimedia sharing sites. Later sections cover social marketing, social computing, crowdsourcing, and online reputation management.