ABSTRACT
This chapter examines Twitter, used by hundreds of millions. It begins with the history of location tagging or geotagging and then the rise of crowdsourced geographic information, which raises a number of issues and questions. It also addresses how Twitter is used, such as continually streamed, spatially differentiated content production. Twitter has been used to analyze geographic trends in word usage, trip generation patterns, and hazards and disaster research. The chapter concludes by examining challenges in the use of Twitter data, such as gender and racial biases, computational dilemmas, and privacy concerns.
