Microsoft announced a couple of weeks ago that they were “retiring” the Windows Live Messenger program, and encouraging users to migrate to Skype which Microsoft bought in May of 2011 for $8.5 billion. This week Microsoft sent out the following email to Windows Live Messenger users encouraging them to move to Skype before the shutdown of Windows Live Messenger. However, there is a catch not everyone had realized. On March 15, what Microsoft is retiring is the Windows Live Messenger program, NOT the Messenger Service
In a communication with Microsoft, the website Arstechnica confirmed what the upcoming changes really cover. As noted by the site Arstechnica
On March 15th, the Windows Messenger client will be blacklisted and unable to connect to the network, informing users that they must install the Skype client instead. The Skype client will continue to connect to the Messenger network (as it does presently) and will allow communication with Messenger users.
Other clients, however, should be unaffected and will continue to connect just fine. This includes both official clients, such as the one built-in to Windows Phone, and third-party software. Users of these clients will be able to chat seamlessly with Windows users using the Skype client.
The one exception is Kinect-based video chat on the Xbox; Microsoft says that too will cease working when the desktop client is retired.
So for now, if you use 3rd party chat clients like Pidgin, Adium, Digsby, and Trillian (among others), you will be able to continue to communicate without any interruption or change. If you use Windows Live Messenger, and you wish NOT to move to Skype, you could always chose one of the 3rd party clients instead.
Source: Arstechnica (http://arstechnica NULL.com/information-technology/2013/01/microsoft-messenger-service-not-going-anywhere-just-yet/)