Transmedia podcasting (transpodcast) is an example of a digital medium essentially promoted by a community of independent creators that arises from the technological advancement derived from the arrival of Web 2.0. This medium is considered to offer its users greater possibilities of participation and co-creation by abandoning the traditional communicative models based on unidirectionality. The objective of this work is to determine how audience engagement takes place in this medium, taking into consideration the analysis of its participation spaces. In order to reach this goal, a Mixed Method Research Design was used, integrating two case studies with a total sample of 2,490 units of participation generated by users on the iVoox platform, the blogs of the two selected projects, and messages on Twitter. The research was complemented with an ethnographic investigation through observational methods on the presence of the user's voice in the podcasts of a total of 19 transpodcast projects. Despite the fact that numerous and relevant voices have defended that the new media ecosystem causes the decentralization and democratization of the agenda-setting and empowers ordinary citizens, this study shows a less optimistic and more critical perspective about the possibilities of meaningful citizen participation in online discourse.