Beware of schemes that claim that your participation in them will help change the world but which come with no money attached. One is only capable of doing great good if one is also capable of doing great evil. More simply: to do a lot of good (not just a teeny tiny bit), one has to be capable of something that affects real world, ergo one has to be powerful. Capability is closely linked with power (and, in a Western society, the closest measure of power is money). If one cannot easily turn his or her work into money, one should question how much capability for real change one has.