Currently, more than half the population in developed countries has experienced online social networking. What is more, a quarter of the world’s citizens now have a profile in social media, whose users number 1.47 billion. Although English-speaking countries top the list of active social media-using nations, people from all around the world are represented in online social network channels. Social media obviously is a global phenomenon; however, we don’t know much about how each nation uses this tool and whether cultural values and demographic factors impact the usage behavior.This book discusses how culture relates to social media use around the world. Chapter 1 summarizes the recent impact of social media on our lives. Chapter 2 describes what social networks are and introduces online social networks. Chapter 3 and Chapter 4 focus on the theoretical aspects of social media. While Chapter 5 connects social media use and human communication, Chapter 6 looks at the effects of social media on society. Chapter 7 is about social innovations. Chapter 8 and 9 provide some basic information about Facebook and Twitter - the two most popular social media platforms - and Chapter 10 looks at the business aspects of social media. Chapter 11 reviews past studies on social media and culture, and Chapter 13 once again talks about Eastern and Western communication styles and how people in the East and West use social media. Chapter 14 compares and contrasts the way Americans and Japanese have been using social media. The last chapter provides a very brief summary of the book.