MAD.exe
(Microsoft)
Windows NT4/2000/XP Server editions only. This service is the System Attendant Service for Microsoft Exchange Server from version 4.0 onward. MAD is a necessary background service for Microsoft Exchange Server some of its many functions : to load the required DLLs whenever you configure Microsoft Exchange, to periodically check if users have been added to the Site and Configuration containers, to write log messages to the Message Tracking Log File on behalf of MTA (Message Transfer Agent) and the Internet Mail Service, to generate the offline address books.