Kiva is non-profit organisation where members can contribute to borrowers all over the world who would otherwise find it difficult to obtain finance for their endeavours.
Most loans are for small businesses although there are also some for education, personal health, home improvements and so on.
Most loans are from less developed nations but quite a few are appearing from the USA recently. I find this a bit unsettling since the USA is by far the richest country in the world, but the distribution of this wealth is incredibly unfair as we all know. You can choose to assist borrowers based on diverse criteria, including gender, country, business or activity, attributes such as green or conflict zones and so on.
There is some debate about micro-finance as a model for assisting others and there is a lot of debate about this on Kiva’s forums. Modern micro-finance was  pioneered by Muhammad Yunus. From Wikipedia, “Muhammad Yunus is a Bangladeshi, social entrepreneur, banker, economist, and civil society leader who was awarded the Nobel Peace Prize for founding the Grameen Bank and pioneering the concepts of microcredit and microfinance.”
The web site is extremely mature, well designed and easy to use. Kiva is reliable, professional and a pleasure to use.
I have been contributing for a few years now. You can see my profile and activity here if you like.