Multi-tenancy support for enterprise social business computing

Mechanisms are provided for enabling collaboration across tenants in a multi-tenant environment using single sign-on (SSO) authentication/authorization. Various examples provide for creating a user account and provisioning a subscription to a user (e.g., to enable single sign-on authentication/authorization). The user is allowed to access services (e.g., collaborative services) in a multi-tenant environment by utilizing a subscription authorization of the user without prompting the user to authenticate by logging-in again (that is, without prompting the user to log-in again after the user has already logged-in and been authenticated for a given session). Other examples provide for mapping webspaces through URL hosts where each organization (that is, tenant) has its own set of namespace(s).