High Quality Content by WIKIPEDIA articles! Windows Messenger is a client by Microsoft that is included in the Windows XP operating system. Designed for use by corporate users as well as home users, it was originally created as a streamlined and integrated version of MSN Messenger. After its initial release in 2001, it was later upgraded in 2004, when it was made available for Windows 2000 and Windows Server 2003.Since then, development on Windows Messenger has stopped, with the exception of security updates. It has been superseded by Microsoft's similarly-named but separate and newer client, Windows Live Messenger, for connections to the .NET Messenger Service, and by Office Communicator in corporate environments.