This paper describes DataONE, a federated data network that is being built to improve access to, and preserve data about, life on Earth and the environment that sustains it. DataONE supports science by: (1) engaging the relevant science, library, data, and policy communities; (2) facilitating easy, secure, and persistent storage of data; and (3) disseminating integrated and user-friendly tools for data discovery, analysis, visualization, and decision-making. The paper provides an overview of the DataONE architecture and community engagement activities. The role of identifiers in DataONE and the policies and procedures involved in data submission, curation, and citation are discussed for one of the affiliated data centers. Finally, the paper highlights EZID, a service that enables digital object producers to easily obtain and manage long-term identifiers for their digital content.