Credible to Whom?
This chapter adopts a case study approach to examine the echo chamber effect online. Individuals cobble together personalized newsfeeds by active choice and those choices are often accompanied by subtle manipulations in social media and online search engine algorithms that may shape and constrain the parameters of information on a given topic. In this chapter, the author studied vaccine-hesitant discourse in an online forum over a five-year period. Those conversations exhibited characteristics of what would be considered an echo chamber, as defined by Jamieson and Cappella (2008). The implications of this case study suggest that the echo chamber within the realm of vaccination can lead individuals toward content and information of dubious veracity, with significant implications for public health.