This book presents the previously untold history of the use of new media in Democratic electoral campaigning over the last decade. Drawing on open-ended interviews with more than fifty political staffers, fieldwork during the 2008 electoral cycle, and archival research, the book follows a group of technically skilled Internet staffers who came together on the Howard Dean campaign and created a series of innovations in campaign organization, tools, and practice. After the election, these individuals founded an array of consulting firms and training organizations and staffed a number of prominent Democratic campaigns. In the process, they carried their innovations across Democratic politics and contributed to a number of electoral victories, including Barack Obama’s historic bid for the presidency. The book contributes to an interdisciplinary body of scholarship from communication, sociology, and political science. The book theorizes processes of innovation in online electoral politics. It shows how the innovations of the Dean and Obama campaigns were the product of the movement of staffers between industries, organizational structures that provided a space for technical development, and incentives for experimentation. The book also analyzes how Dean’s former staffers created an infrastructure for Democratic new media campaigning after the 2004 elections that helped transfer knowledge, practice, and tools across electoral cycles and campaigns. The book shows how organizational contexts shaped the use of tools by the Obama campaign, analyzes the emergence of data systems that facilitate electoral coordination, and reveals how cultural work mobilizes supporters to participate in collective action.