Windows Live Messenger

Windows Live Messenger (previously also known as MSN Messenger and Windows Messenger) was a messaging service from Microsoft. It was launched on 22 July 1999 and discontinued on 8 April 2013 with the migration to Skype, although the client protocol has since then been reversed and the clients can now be used with unofficial servers.

Availability
MSN or Windows Messenger is available as a component of Windows Me and XP. For older systems, there were either stand-alone installers in form of IExpress, as well as the installer for Internet Explorer 5.5, which included the messenger as an option. It is also available in pre-reset builds of Longhorn, but was scrapped from the installation image after development reset. Since then, Windows Live Messenger needed to be downloaded from the Microsoft web site. It can be installed standalone or as part of the Windows Live suite. With the EOL of the Windows Essentials 2012 in 2017, it is no longer available for download at Microsoft.