Utilisation of internet-derived information by patients within the healthcare service encounter is increasing. Encompassing both the use of unidirectional information sites as well as bidirectional computer-mediated communities, this is manifest in the growth of consumerist expectations on the part of patients. Based on interviews with patients, professionals and internet site managers, this paper examines the role of the internet as a source of patient information and support, and in particular the effect on the relationship between 'informed' consumers and professionals involved in the delivery of healthcare services. The core challenge for informed consumers is to develop frameworks that facilitate robust dialogue, exchange of information and emotional support to complement their rising authority. The parallel challenge is for the established medical profession to recognize the consequences of this evolving dialogue and develop approaches to service delivery that effectively engage with consumers on the basis of this increasing authority. © Health Services Management Centre 2004.