Book excerpt: From Facebook and YouTube to TikTok and WeChat, this accessible book explores the relationships between public and personal communication on social media to understand their impacts on users’ everyday lives. Social media have made possible new kinds of relationships, entertainment, and politics, and enabled billions of people to experience new forms of communication, community, and communion. But social media are also profit-driven, data-mining corporations, and their core business model is often built around targeted surveillance that enables the commercial exploitation of their users’ everyday lives. Graham Meikle explores the tensions between these different dimensions of social media, engaging with questions of communication, data, remix, news, visibility, citizenship, and regulation. This second edition has been substantially revised: more than half of the text is entirely new to this edition, and those sections that remain have been completely updated. This new edition includes analysis of the data-driven business models of major social media firms, and of how these firms are expanding into new areas such as AI. It also includes discussion of major developments in news, surveillance, and activism on social media, as well as a new chapter on regulation. This book is an ideal critical introduction to social media in all their complexity.