The competition between various instant messaging clients, and its protocols or services. From the pioneer ICQ, more and more IM services such as Windows Live Messenger (previously known as .NET or MSN Messenger), AOL Instant Messenger, Google Talk, iChat, Jabber, Qnext, QQ, Meetro, Skype, Trillian, Yahoo! Messenger, Excite/Pal, Gadu-Gadu, and Rediff Bol Instant Messenger available on the public Internet, competing with other multi-protocol instant messaging client such as Pidgin (previously known as Gaim). But who’s the winner in this IM war?

According to comScore Networks report done in February 2006, 61 percent of worldwide IM users use MSN Messenger application which has been renamed to Windows Live Messenger (WLM), making MSN Messenger the IM client with highest popularity and penetration rate. MSN Messenger even commands more than 90 percent of IM users in Latin America, and more than 70% IM users both in Europe and Asia Pacific.

It looks like the popular belief that AOL Instant Messenger or AIM is leading IM client is simply a myth. AIM is popular in North America, and only in North America, engaging in three corner fight with MSN Messenger and Yahoo! Messenger, with each garnering between 27 percent and 37 percent of IM users.