Development of client applications within the Microsoft Exchange Server environment is accomplished by either extending the Microsoft Exchange Client, or by creating stand-alone client applications.
You can build Microsoft Exchange Server client extensions that add functionality to the Viewer, such as new pull-down menus or function keys.
Other possibilities for extension development include:
You can also develop your own client application. Most client applications interact with Microsoft Exchange Server by retrieving data from the information store, placing information in a public folder, or manipulating messages to be sent or posted. Your application can perform actions similar to those of the existing Microsoft Exchange Client, or it can supply new functionality.
An example of a unique client application is the Microsoft® Schedule+ client that is provided with Microsoft Exchange Server, as well as with the Microsoft® Windows NT® and Windows® 95 operating systems. Schedule+ enables users to schedule group meetings, manage their daily appointment schedules, track projects and tasks, maintain lists of contacts, and perform many other time- and resource-management tasks. The characteristics of the Schedule+ client are founded on the functionality and features of Automation and can be customized using the Schedule+ Automation interface.