Indeed. I don't know about today, but back in 2006 MSN was as popular as AIM and Yahoo! worldwide and particularly strong in certain areas -- there are some countries where it was even a verb ("I'll MSN you"). But then MS changed the name to "Windows Live Messenger", underinvested, and prioritized search instead. Ah well.

is. I was just all over Central and South America, and internet cafes were always full of high school kids, every single screen full of MSN chat windows.

Indeed, here in Argentina MSN is the default chat application.

My understanding is that MSN was/is the most popular IM service most everywhere but the US (because of AIM?) and East Asia (where they have their own regionally popular services, like QQ in China).