From huffpost, of all places:
Warren has used his fame and fortune primarily to help the most destitute people in the world. He reverse tithes, giving away 90% and keeping 10%. Please contemplate all the religious figures who have gotten rich off their flock and pocketed the money. Who among you reverse tithe or would if you were rich? I know I don't, and every time I think about what Warren has done it makes me question whether I'm giving enough.
(Hat tip: Frum)