Drawing on the results of a long-term research project into the network structure of the Australian Twittersphere, combined with an investigation of audience participation through social media in selected reality TV and political debate shows, this paper maps the location of the Twitter communities participating in the social TV components of the selected shows onto the underlying follower/followee network structure of the Australian national Twittersphere. In doing so, it addresses questions about the homology or distinctions between the social TV audiences for the different shows; the correlation between existing follower/followee relationships and participation in specific social TV activities; and the effects of Twitter activity related to specific shows in making these shows visible to the entire national Twitter network. The development of such network-based approaches to the quantification and visualisation of social TV engagement makes another important to the development of reliable and generally applicable metrics for social television.