Take a look at this map from Jeff LaPorte:

I wonder if this shows some sort of era-of-adoption effect, where folks in the US had widespread Internet access so they got started with AIM and never switched, then Canada and Australia picked up Messenger, and other places see a popularity of even more recent clients? Or perhaps it’s an artefact involving what kind of people use a messenging-interop solution? Whatever the mechanism, I’m a typical Canadian I guess since I use Messenger.

Kate