Extending organizational boundaries throughout a cloud architecture

An information sharing paradigm for a cloud computing solution enables flexible organizational boundaries with respect to cloud resources. Cloud service customers manage their own organization boundary but can extend that boundary selectively by associating cloud resources they own with sets of domain names that may be associated with requests for cloud resources that the organization may be willing to share with other organizations that are using the cloud environment, and by ensuring that any such requests for resources that are shared in this manner are associated with one or more message handling policies that have been defined by (or otherwise associated with) the resource-owning organization. Cloud resources owned by an organization (even those marked as “internal only”) may be selectively shared with one or more other organizations using the cloud environment depending on the domain names associated with the requests. Message handling policies are enforced with respect to shared resources.