Collaboration Data Objects 1.21 - CDO 1.21 (aka Active Messaging and OLE Messaging)

An application programming interface (API) that allows users and applications to access data objects within a server running Exchange. CDO defines the concept of different object classes including messages (IPM.Note), posts (IPM.Post), and appointments (IPM.Appointment). Message stores and folder hierarchies can also be manipulated through CDO 1.21.

CDO 1.21 is included with Exchange Server 5.5 and its services are supplied from the CDO.DLL file [Exchange 2000]