"An accessible and wide-ranging introduction to the dirty work of cleaning up the internet."—Anna Lauren Hoffmann, Science

"In this lively and entertaining book, Tarleton Gillespie shows us how social media regulate our speech in many different ways, some overt and some hidden. He explains why content moderation is not a peripheral function of social media, but central to their very existence."—Jack Balkin, Yale Law School

“Online platforms are defining our technological landscape, shaping our lives online and off. Custodians of the Internet is the exquisitely-drawn map that shows us how they do it.”—Jonathan Zittrain, author of The Future of the Internet and How to Stop It

“In this timely and important book, Gillespie deftly reveals the factors that shape social media platforms, and thus our world. Clear-eyed and incisive, a must-read for anyone interested in the influence of platforms, the forces that structure this influence, and crucially how to move forward.”—Zeynep Tufekci, contributing opinion writer for The New York Times and author of Twitter and Tear Gas

"Truly stellar. Gillespie’s analysis deftly contextualizes moderation policies on social media platforms, and illuminates how the platforms' underlying values are baked into these policies. The result is essential reading."—Whitney M. Phillips, author of This Is Why We Can't Have Nice Things: Mapping the Relationship Between Online Trolling and Mainstream Culture

“No one knows how digital platforms are shaping our lives better than Tarleton Gillespie. This book is an essential guide to the social and technical processes that animate our new media – and to the principles by which we might put them to more democratic ends.”—Fred Turner, author of The Democratic Surround: Multimedia and American Liberalism from World War II to the Psychedelic Sixties