Crisis in a Tweet explores the alarming reality that a single social media post can unleash severe consequences for individuals and organizations alike. Unlike traditional emergencies caused by natural disasters or product failures, social media upheaval originates in the digital realm but leads to real world consequences - job losses, reputational harm, and public shame - disproportionate to the original act. This book provides a comprehensive analysis of how social media platforms serve not just as communication tools but as environments for the emergence of crises. Drawing on case studies from platforms like X, Facebook, and YouTube, this book outlines a fundamental shift in media ecology, where everyday digital interactions become amplified into firestorms. It investigates key drivers of this trend, including the democratization of crisis creation, the amplified effects of online mobs, and the rise of partisan communities weaponizing outrage.From the unearthing of old posts to viral hashtag movements fueling global reputational attacks, this book explains how digital crises differ from traditional ones and why society assigns them outsized significance. Rather than advocating for more regulation and prevention, Crisis in a Tweet calls for a cultural shift in how we perceive and respond to online controversies.