How it works: Retailers offer prepaid mobile phone cards, accessories and even handsets from streetside kiosks and shops.

Why it's important: Mobile phones have revolutionized life in developing countries, as households that never had access to electricity or landline phones use mobile phones for everything from comparing the prices of farm produce in neighboring markets to receiving remittances from family overseas. By enabling communication in places without much public infrastructure, mobile phones smooth fluctuations in food prices and make it easier to hold political leaders accountable.

What your loan can do: Larger amounts of capital make it possible for mobile phone retailers to upgrade their inventory, offering affordable smart phones for the first time. Or they can offer services such as prepaid data subscriptions and even mobile phone-based money transfers.