This anthology addresses ethical challenges that arise within the field of Internet research. Among the issues discussed in the book are the following: When is voluntary informed consent from research subjects required in using the Internet as a data source? How may researchers secure the privacy of research subjects in a landscape where the traditional public/private distinction is blurred and re-identification is a recurring threat? What are the central ethical and legal aspects of Internet research for individuals, groups, and society? With contributions from: Dag Elgesem on informed consent, Charles Ess on over-individual ethics, Anders Olof Larsson on methodology, Marika Lüders on confidentiality and anonymity, Robindra Prabhu on Big Data, Katrine Segadal on legal requirements, Elisabeth Staksrud on counting children and Kari Steen-Johnsen and Bernard Enjolras on constraints on online social research. The Norwegian National Research Ethics Committees are independent public agencies providing guidelines and addressing questions regarding research ethics in all subject fields.