Online communities have displaced or become complements to organizations such as churches, labor unions and political groups which have traditionally been at the center of collective action. Yet, despite their growing influence and support of faster, cheaper and more flexible organizing, few empirical studies address how online communities are built and become enduring agents of social change. Using Internet-based ethnographic methods, this inductive field study examines how an online community called Anonymous transitioned from being a small gathering of contributors focused on recreation to becoming a community of trolls, activists and hackers incubating myriad projects. Findings reveal that the interplay of digital technology and a culture of transgression supported experimentation that culminated with the adoption of a resilient organizing platform that enabled several community factions to coexist in continuous engagement. This paper infuses community building research with an important emphasis on the role of the techno-cultural, highlighting how online formation and maintenance processes are shaped and shape mutually contingent technologies and cultures.