Great idea! I was about to wite a post about the same topic.

I think that steem opens huge possibilities for found raising and it will even better when EOS will be launched and someone will create a platform specific for charity purpose.

I am in touch with two onlus association ( http://www.axeitalia.net & http://www.pesciolinorosso.org ) and I will assist them in the process of joining the steem community and raise funds throught creating content. It would be a great experiement! Stay tuned!