"The hashtag is everywhere--but why and what does it do? In this small book, Liz Losh insightfully answers this question through historical research, case studies, and rhetorical analyses that explore the possibilities, dangers, and limitations of #CommunicateThis; #HijackThis; #DoesThisReallyMakeADifference. Brilliant and compellingly written, it takes on #controversies and helps us understand how gender, race, and labor matter." -- Wendy Chun, Canada 150 Research Chair in New Media, Simon Fraser University, Canada, and author of Updating to Remain the Same: Habitual New Media (2017) "This is the story you didn't know existed--the story of how one little symbol enabled efficient and powerful communication among human beings and between computers. The hashtag is one of the most interesting communicative inventions of this century. Dr. Losh explains how it got this way in clear language and with an eye for detail." -- Siva Vaidhyanathan, Robertson Professor of Media Studies, University of Virginia, USA, and author of Antisocial Media: How Facebook Disconnects Us and Undermines Democracy (2018).