This paper explores the critical role of conversational threads in facilitating the ongoing, distributed work of one virtual organization. In studying the electronic mail exchanges of organizational members during one year, we found that they engaged in a range of threading activity to establish and maintain continuity, coherence, and coordination in their collaborative work over time. In particular, we found that organizational members relied on simple threads to focus their attention and action on a particular topic over a short period of time, concurrent threads to enable their participation in multiple topics at the same time, and compound threads to allow provisional settlement of key issues that were subsequently revisited over extended periods of time. We conclude by discussing the implications of conversational threads for research and practice of virtual organizing.