The Microsoft® Exchange Event Service generates events on folders. An agent is a handler (a script) written to respond to those events. You can take advantage of folder events in either of two ways: by writing your own agent or by using the Microsoft Exchange Server Routing Engine, which itself is a custom agent that runs under the control of the Exchange Event Service. All agents, including the routing engine, are configured on a per-folder basis and respond to the events generated by the Event Service on that folder.
Custom agents are written in Microsoft Visual Basic® Scripting Edition (VBScript). Agents are coded to have one routine respond to each event as it occurs in the folder. The agent for LitCrit is simple because its tasks are simple: route newly posted critiques to an approver, handle posting of approved critiques, handle edits of existing critiques, and so on. If the tasks for this application were more complex, the developers of LitCrit would have instead created a routing map, which the Exchange routing engine uses to guide a document (such as an Outlook® form) through a path in the organization. For more information, see About the Routing Engine, Routing Objects, and Routing Maps.