Messenger for Mac is described as 'Messenger:mac (or Microsoft Messenger for Mac) is Microsofts version of the popular Windows Live Messenger for the Mac platform' and is an app in the Social & Communications category. There are more than 10 alternatives to Messenger for Mac for a variety of platforms, including Mac, Windows, Linux, Online / Web-based and Android. The best alternative is Skype, which is free. Other great apps like Messenger for Mac are Pidgin (Free, Open Source), Hangouts (Free), Facebook Messenger (Free) and Whereby (Freemium).
Skype is the most popular free voice-over IP and instant messaging service globally. It allows users to text, video and voice call over the internet. Users can also call landlines and mobiles at competitive rates using Skype credit, premium accounts and subscriptions.
Pidgin is an easy to use, multi-protocol chat client client used by millions. Connect to AIM, MSN, Yahoo, XMPP, and more chat networks all at once. It has built-in support for NSS, offering client-to-server message encryption for protocols that support it.
Kopete is an instant messenger supporting AIM, ICQ, Jabber, Gadu-Gadu, Novell GroupWise Messenger, and more. It is designed to be a flexible and extensible multi-protocol system suitable for personal and enterprise use.