This methods case study is based on my doctoral research project, which aims to understand contemporary psychostimulant use within the socio-cultural context of Western societies. The research design is founded on a web-based ethnographic approach. Such approaches are called upon to a lesser extent in public health research; however, they are becoming increasingly indispensable considering that everyday life is enacted more and more both online and offline. Furthermore, these methods are particularly well suited to understand practices that can be stigmatized, such as drug use. Results stemming from such research can help shape policies and interventions that aim to reduce harms associated with drug use as an alternative to more prohibitive approaches. This study focuses on three publicly accessible online discussion fora belonging to the Reddit website. Nonparticipant observation was performed over a period of 18 months to observe exchanges between members, interactions with moderators, and aesthetic elements. In total, 331 postings were collected from the selected fora for qualitative analysis. Although similarities exist between traditional ethnographies and web-based ones, there are important particularities to be considered, notably concerning the position of the researcher, data collection and analysis, as well as ethical aspects.