Launched in 2007, tumblr became a safe haven for LGBT youth, a launch pad for social justice movements, a NSFW rabbithole, and a counselling station for mental health issues. For a decade, this micro-blogging platform had more users than Twitter and Snapchat, but remained an obscure subculture for non-users and most researchers. In 2018 it catapulted to popular consciousness by banning all NSFW content, shifting to rigid censorship almost overnight. Tiidenberg, Abidin and Hendry offer the first overarching, holistic and systematic guide to tumblr and its crucial role in shaping digital culture. Drawing on nine years of in-depth, qualitative data, they reveal why tumblr is 'special' by examining how it has developed, where it belongs in the social media ecosystem, and its prominent practices of creativity, curation and community making. Throughout, the book explores how diverse social media cultures can coexist on a single platform, and how destructive the recent trends in platform governance can be. The authors introduce the concept of 'silosociality' to describe the intensely affective and often-sequestered structures of feeling that organize users' experiences of tumblr, and challenge the assumptions commonly made about how social media functions and what role it plays for individuals, groups and culture. A groundbreaking contribution to the study of social media, this book is an essential resource for students and scholars of media and communication, as well as anyone interested in an influential but overlooked platform.?