The Pirate Party of Germany (PPG) and the Italian 5-Star Movement (5SM) are two digital movement parties that share several ideological features, including their roots in anti-establishment movements, their refusal to position themselves on the Left-Right spectrum, and their belief that the Internet increases the capacity of ordinary citizens for self-government and self-representation. To this end, both parties have adopted online participation platforms, which allow their members to contribute to the development of the party program, vote on strategic decisions, and propose policy initiatives. Given these affinities and given that both parties begun their political ascendancy in the same years, their antipodal political destinies – ascendency to power for the 5SM, downfall for the PPG – are all the more striking. This article accounts for this divergence by showing how the technopopulist orientation of both parties conceals in fact radically different conceptions of political participation and internal party democracy. To this end, it considers the role that different technopolitical cultures have played in shaping the organization of these two parties in their early stages, and how the subsequent adoption and use of online participation platforms has led to internal strife and bitter disputes within the PPG and increasing centralization within the 5SM.