This month, as a crisis in a small sub-section of the US housing market created havoc around the globe, media attention has focused on high finance and the linkages between the world's big economies.

But there is another compelling story of economic integration and global mobility of money that is arguably more important to more people than derivatives and off-balance sheet investment funds. It is the story of remittances, the poor man's counterpart to arcane financial innovations, and how they have wrought vast and visible changes in many developing countries.