The past decade has witnessed an emergent form of activism increasingly defined by its reliance on internet strategies, network social structures and participatory practices. Internet strategies employed by many contemporary activists include websites, listservs and hyperlinked networks used for exchanging information, mobilizing both old and new constituencies, and coordinating collective action. Networks of organizations and individuals are formed both on and offline and decision-making within these groups is often made by consensus. Perhaps best characterizing this activism is its lack of hierarchy, epitomized by democratic communications, both within and between networked organizations. This article focuses on Indymedia, a prime institutional exemplar for the indicators mentioned above internet-based activism, network formation and participatory politics. Specifically, it addresses issues related to sustainability and political efficacy in radical democratic activist networks that are increasingly enabled by internet technologies.