I'm able to help, because I have a good-paying steady job and more money than I need to sustain a good and happy life and therefore I have a responsibility to share that surplus which I do not need with my neighbours in less fortunate circumstances.
I also think Kiva is great concept; I donate to local and international aid agencies who help people in need with medicines, accommodation and such but there's more to life than just having somewhere to sleep and something to eat - and I think Kiva and their partner agencies helps people and particularly entrepreneurs realise their dreams and achieving something in building better lives for themselves and their community at a level above just basic needs.