"Problems are not always obvious from afar (You really have to live for
a while in a society where no one has currency larger than a $1 bill to
understand the importance of money via mobile phones.)"
I think problems (and solutions) are around us. You don't have to live in Africa, to see powerty. Try to help the poor people around you. I dare anyone to say, they don't pass someone poor on the street almost every day.
I think it's easier to help poor people around you, and then use that knowledge to help other people more far away.
That could be good start.