This book is intended for applications of online digital mapping, called mashups (or composite application), and to analyze the mapping practices in online socio-technical controversies. The hypothesis put forward is that the ability to create an online map accompanies the formation of online audience and provides support for a position in a debate on the Web. The first part provides a study of the map: - a combination of map and statistical reason- crosses between map theories and CIS theories- recent developments in scanning the map, from Geographic Information Systems.