Hosted organization (aka virtual server, virtual machine, virtual organization)

A collection of Exchange services including, but not limited to virtual servers (that is, instances of IMAP4, SMTP, POP3, NNTP, HTTP, RVP), storage space, and real-time collaboration facilities that exist to serve the needs of a single company. A hosted organization is normally used by Internet Service Providers to host multiple companies on the same physical computer. However, a hosted organization is not limited to a single server running Exchange 2000. [Exchange 2000]