This paper argues that the plethora of experiments with decentralized social technologies (DSTs)—clusters of which are sometimes called “the Web 3.0 ecosystem” or “the Fediverse”—have brought us to a constitutional moment. These technologies enable radical innovations in social, economic, and political institutions and practices, with the potential to support transformative approaches to political economy. They demand governance innovation. The paper develops a framework of prudent vigilance for making ethical choices in this space that help to both grasp positive opportunities for (...) transformation and avoid the potentially problematic consequences. Most of our specific examples and concerns come from the blockchain/Web3 universe, as this has received the greatest investment, attention, and adoption to date. However, we aim to offer a framework for governance decision-making in conditions of uncertainty that applies more broadly to other DSTs. Specifically, under the framework of prudent vigilance, we propose a pragmatic, democratic, and pluralist approach to navigating bold experimentation with social practices and political economy enabled by these technologies. Our overarching goal is to provide a framework open to transformative improvement and constrained by guardrails and guiding values supportive of democracy, freedom, and pluralism. We take a relatively strong position, rather than simply laying out ethical issues and potential approaches. We seek to be provocative in order to spur further work and hope this paper will serve as a first bridge between academic philosophy and the DST community, which have hardly interacted to date. (shrink)