Abstract:The core technology of eScience is the connection of distributed resources such that they appear as one virtual instance, enabling the collaborative research work on the Internet on that shared virtualized resource. eScience first embraced shared resources through support of "big science" in the Grid computing field. By contrast, emerging cloud services make high-end eScience infrastructure such as shared computing and disk resources affordable to common researchers. Though there are many such services to choose between, users always have to be authenticated as a researcher and authorized when they utilize services provided by a given collaboration. Effectively leveraging the world-wide deployment of academic identity federations may allow us to build a complete and coherent eScience environment more securely, easily, and scalably. One marked recent tendency in Identity Federation is to support virtual organization (VO), organizations composed of individuals principally domiciled at and authenticating against an organization but acting in a particular role within the virtual organization. A similar theme also emerged in Grid computing. However, all known current schemes have no common method for sharing VO information because every virtual organization is, today, largely bespoke, and these custom-built implementations take into account the principal needs of the federation and country and project where the VO emerged, leading each federation to employ different standards in integration with VO's and provision of information to VO's. This paper offers a historical perspective on VO technology, first by assessing its evolution in the Grid computing field followed by an analysis of progress in broader identity federation. Finally, potential evolutionary paths are divided into three natural categories, and we perform a technical and operational comparison of current VO technology and its capacity to meet these new use cases today and in envisioned futures. Reflecting how much development and operational costs are acceptable for each party concerned, two of these are considered preferred choices for the short-term and long-term transition to the unified, global VO platform.