There are many reasons to do things other than money, but when you are dealing with people that you don't personally or directly know the fact that they are wil

There are many reasons to do things other than money, but when you are dealing with people that you don't personally or directly know the fact that they are willing to pay for your services is basically the only real signal you have as to whether you are benefiting them. And if you are not making more doing this (for a combination of monetary and non-monetary benefits) than you could something else, then you need to switch to a better use of your time. Of course, the contributors benefit from donating money, etc by signalling effects and warm fuzzies, but that doesn't mean the recipients are benefiting nearly as much as the contributors are spending.