Social media has democratized information by allowing users to publish content in addition to consuming it. It has transformed one-way broadcasting into two-way conversations. Key social media platforms include Facebook, Twitter, YouTube, and blogs. While traditional media was controlled by editors, social media is driven and controlled by users. It also faces less censorship. Marketers can use social media to expand campaigns, improve customer service, and build relationships. Measurement of social media success includes both quantitative metrics like website traffic and qualitative factors like sentiment. Effective social media use involves listening, engaging, and refreshing content regularly.