This study looks at the communication between users concerning health risks, with the aim of exploring their use of fora and assessing whether participants establish a niche with like-minded users during these exchanges. By integrating a corpus linguistic approach with content analysis and multiple studies on computer mediated health discourse, this study analyses the intense attention paid to the correlation between the Measles Mumps Rubella (MMR) vaccine and autism, as an example of elaboration of the message and risk of emotive amplification, with fora working as echo chambers. Results include: a) a qualitative analysis of the content of posts and their qualification, b) a focus on the type of concerns questioners raise, and c) a comparison of the qualifier proportions between the posts and the responses they get. The comparison between posts/responses investigates whether the forum works as an amplification station of emotions, or as a locus to establish a belief niche
