MSN Messenger was once Microsoft's flagship messaging system and social networking platform, in a time before Facebook, Skype, Discord, or Twitter.
Retrieved on April 20, 2012.
A few years later, the Redmond-based tech giant reached an interoperability that would allow users of their respective IM services to chat with each other.
You will be asked to sign in with your Microsoft account.
The first version of MSN Messenger Service, version 1.
Also, you may check this containing our FAQ's regarding Skype.
Needless to say, AOL was not thrilled.