After March 15, the Windows Live Messenger will only be available for use in Mainland China wil, mainly because Skype is operated there by a local provider called TOM.
As you can see, the email in question is titled “Important info about your Messenger account.” Here’s the main part:
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 progress of transition from Windows Live Messenger to Skype is very simple. Skype will give you the option to merge your own accounts, as well as message both types of contacts.
Messenger users will have to download and install Skype. Then, use their Microsoft Accounts to log in and all their Messenger contacts should be available inside.
Probably the bigger reason for Microsoft shutting down Messenger is because they have bought skype back in May 2011 for $8.5 billion. Now Microsoft is trying to push users to the latter service.
Until the complete transition to Skype take places on March 15, you can use Messenger as you would normally. You’ll just see the addition of a banner asking you to download Skype. Once March 15 comes you won’t be able to log into Messenger and instead you’ll be taken to a page that prompts an installation process for the Skype client onto your desktop. The same process will also uninstall Messenger from your computer forever.