Collaboration Data Objects

Originally known as Active Messaging, the Collaboration Data Objects (CDO) library allows you to access the Global Address List and other server objects, in addition to the contents of mailboxes and public folders. It is the principal model used for Exchange Server Scripting (Exchange 5.5) and is also used for some key Outlook programming tasks, such as displaying an address book for the user to pick from. However, with the advent of the Outlook Email Security Update, CDO is far less useful, many developers are using Redemption instead in order to avoid the security prompts.