Sarah Palin took a lot of (probably unjustified) grief for saying that Africa was a country, not a continent, but I have to say that understanding is probably deeply embedded in a lot of us. I heard it today when Barack Obama was announcing the Secretary of the Treasury and said that "Growing up partly in Africa" had given him perspective on global markets--and it does. But I was surprised to find myself instantly wondering "Where in Africa?" knowing now better than before that "Africa" is not a country, and to grow up in Africa doesn't tell me as much as I think it does.
Incidentally--and significantly--the African nation where Geithner spent some of his youth was Zimbabwe, a country with a sad history of economic disaster.