Microsoft announced on November 2012 it would soon retire its instant messaging client in favor Skype, which Microsoft acquired in October 2011. On January 8,2013 it began informing Messenger users that the service would go dark for the majority of users on March 15, 2013.
On 15th March 2013 we are retiring the existing Messenger service globally (except for mainland China where Messenger will continue to be available) and bringing the great features of Messenger and Skype together. Update to Skype and sign in using a Microsoft Account (same as your Messenger ID) and all your Messenger contacts will be at your fingertips. You’ll be able to instant message and video chat with them just like before, and also discover new ways of staying in touch with Skype on your mobile and tablet.
The Messenger Team