Applying multimodal textual analysis to the languages and images of on-line communication forms, Kay Richardson shows, from an applied linguistic perspective, how the Internet is being used for global, interactive communication about public health risks. Detailed case studies of the possible risks posed by SARS, by mobile phones and by the vaccination of babies against childhood diseases are presented in depth. The author also explores the way in which, through their talk online, people appear to judge the mass media coverage of these topics. The analysis is qualitative rather than quantitative, and is situated within the context of research on computer-mediated communication, as well as within the broader social context of globalisation and discourses of risk and trust. Beyond the linguistic and online communication aspects, the book will interest anyone concerned with the issue of public perceptions of significant health risks.