Извините, но про
протокол MAPI я не слышал. Есть IMAP.
Цитата:
MAPI (Messaging Application Programming Interface)
A messaging architecture and a client interface component.
As a messaging architecture, MAPI enables multiple applications to interact with multiple messaging systems across a variety of hardware platforms.
As a client interface component, MAPI is the complete set of functions and object-oriented interfaces that forms the foundation for the MAPI subsystem's client application and service provider interfaces. In comparison with Simple MAPI, Common Messaging Calls (CMC), and the Active Messaging Library (CDO), MAPI provides the highest performance and greatest degree of control to messaging-based applications and service providers.
CDO Microsoft® Collaboration Data Objects
A technology for building messaging or collaboration applications. Also called OLE Messaging; in version 1.1 it was called Active Messaging. It is designed to simplify the creation of applications with messaging functionality, or to add messaging functionality to existing applications.
CDO is MAPI shell, or in other word, CDO does not represent a new messaging model, but rather an additional scripting interface to the Messaging Application Programming Interface (MAPI) model.