MSN Messenger

MSN Messenger (colloquially known as simply MSN), later rebranded as Windows Live Messenger, was a cross-platform instant messaging client developed by Microsoft. It connected to the Microsoft Messenger service while also having (as of the final version) compatibility with Yahoo! Messenger and Facebook Messenger. The client was first released as MSN Messenger Service on July 22, 1999, and was marketed under the MSN branding until 2005 when it was rebranded under Windows Live. It has since been officially known by its second name, although its first name was still used colloquially by most of its users. In June 2009, Microsoft reported the service attracted over 330 million active users each month, placing Messenger among the most widely used instant messaging clients in the world.

Versions of MSN/Windows Live Messenger were released for Windows, Xbox 360, Mac OS X (later under the name Microsoft Messenger for Mac), BlackBerry OS, iOS, Java ME, S60 on Symbian OS 9.x, Zune HD, Windows Phone, Windows Mobile and Windows CE.

Following the acquisition of Skype Technologies in May 2011, Microsoft added interoperability between Skype and Microsoft accounts, allowing Skype (which had features unique to its platform and a wider user base) to communicate with Messenger contacts. In 2013, Windows Live Messenger was discontinued and Microsoft began ceasing service to existing clients. The service in China remained active for another 18 months, and ceased operations on October 31, 2014.