You provide part of the computing power of your computer, mobile phone, or tablet for solving mathematical computations. While mining on your own such a contribution would be rather small, by mining with the charity-mining community you can make a significant impact on a wide range of charitable projects. See our slides here for a detailed explanation.
This depends on the price of electricity. In some countries it can be more efficient to do charity-mining, while in others it might be more efficient to donate to charities directly. Either way, if you cannot or do not want to donate directly, then charity-mining is a great option through which you can have a positive impact on society with little effort -- even while working in a library or on a train! We are collecting more information about the efficiency here.
A small share of what you’re mining is directly donated to CO2 compensating initiatives. This way, even if the electricity you’re using is not generated sustainably, possible CO2 emissions are compensated for. If you’re using renewable energy though, then you’re even doing good for the global CO2 balance. Details on how we calculate the compensation can be found here.
In order to run independently of different cryptocurrencies (such as bitcoin, ethereum or monero) we display your contribution in terms of a different unit which we call charity coin. The value of one charity coin is tiny, but here we show how much the community can generate in a month in USD given the current value of a charity coin.
Yes it does, however for many devices it is still more effective to mine than to directly donate money. See our efficiency studies. As an additional benefit, during winter, you can reduce your heating costs, since the power used by your computer is almost fully transformed into heat.