This document discusses social media and its key characteristics. It defines social media as mediated communication that enables two-way interaction within online social networks. This blurs the lines between personal and mass media. Social media is characterized by increased participation, remediation of existing media forms, and a culture of bricolage where users create new content by combining pieces from different sources. The document outlines both opportunities and challenges of social media relating to areas like social implications, business, legal issues, and culture.