Online giving marketplaces allow for the transfer of funds from interested donors and lenders to those who need them. In this new philanthropy space, it is as yet, unclear whether the donor is the "supply" or the "demand," and organizations are just beginning to experiment with the utility of such online functioning. In this panel discussion, sponsored by the Stanford Center for Social Innovation, philanthropy experts working at online marketplaces discuss how their organizations function and what differentiates them from others.