Microsoft created Windows Live Messenger as "MSN Messenger Service" in 1999. It was renamed to Windows Live Messenger later.
The first version of MSN Messenger Service, version 1.0 (1.0.0863), was released July 22, 1999. It included only basic features, such as plain text messaging and a simplistic contact list. When it was first released, it featured support for access to America Online's AIM network. America Online continually tried to block Microsoft from having access to their service until eventually the feature was removed, and it has not re-surfaced in any later versions of the software. Since then, the software has only allowed connections to its own service, requiring a Windows Live ID account to connect.
Microsoft released the first major update, version 2.0 (2.0.0083), on November 16, 1999. It included a rotating advertising banner and the ability to customize the appearance of the chat window. It came as an install option for Windows Me. This version was followed the next year by version 3.0 (3.0.0080), which was released May 29, 2000. It included file transfers and PC-to-PC and PC-to-phone audio capabilities with Net2Phone, one of the first VOIP providers.
Along with the release of Windows XP came version 4.6 of MSN Messenger, on October 23, 2001. It included major changes to the user interface, the ability to group contacts, and support for voice conversations. In this version, the client software was renamed from "MSN Messenger Service" to just "MSN Messenger," while the underlying service became known as ".NET Messenger Service," the name it has kept ever since. This version was only compatible with Windows 95, 98, Me, NT 4.0, and 2000, because Microsoft provided a scaled-down new program for Windows XP, called Windows Messenger, that it originally intended to replace MSN Messenger with on Windows XP.
That strategy changed when version 5.0 of MSN Messenger was released on October 24, 2002. It was the first version that was allowed to be installed along with Windows Messenger on Windows XP. It included UPnP (Universal Plug and Play) based file transfers, minor changes to the user interface artwork, and a Windows Media Player interface plug-in.
The next year, version 6.0 of MSN Messenger was released July 17, 2003. MSN Messenger 6.0 was a major overhaul of the whole platform, upgrading its simple text-based interface to include customizable elements such as emoticons, personalized avatars, and backgrounds. An update, version 6.1, focused on improvements to the conversation window, enabling users to hide the window frame and menu bar, and also the ability to change the theme color. The theme color could be set differently for each user. Another update, version 6.2, was released April 22, 2004, and it was the last version of the MSN Messenger 6 series. The most notable changes were a dedicated Mobile group for mobile contacts, a connection troubleshooter, and the Launch Site feature was renamed to Fun & Games.
MSN Messenger received a major upgrade to version 7.0 on April 7, 2005. This version brought wink features that were previously only available in threedegrees. This version also advertised items to sell to you including animated display pictures, emoticons and backgrounds. The contact list window style was also updated to match instant message windows. This version also introduced the Xbox Live Integration feature. This is the last version of MSN Messenger that runs on Windows 98 and Windows Me. This version also introduced digital ink and handwriting recognition support.
The last version of MSN Messenger before the name change, version 7.5, was released August 23, 2005. New features included the Dynamic Backgrounds feature and the "msnim" protocol handler, which allowed Web sites to provide links which automatically add a contact or start conversations. Additionally, a new Voice Clips feature allowed users to hold down F2 and record a message for a maximum of 15 seconds and send it to the recipient. The window for conversations was changed slightly with an added video button. This version also introduced the Windows Installer for its auto-update feature. You still can run MSN Messenger 7.5 by changing the compatibility settings to Windows 2000.