The prevailing theory of charity law holds that the charitable contribution deduction is justified because it solves market and government failures in charitable goods by compensating for free riding on charitable contributions. This Article argues that many market and government failures in charitable goods are actually caused by transaction costs, and that social technology can solve those market and government failures by reducing transaction costs. Specifically, it shows that in the early twentieth century, the social technology of charity chain letters solved market and government failures in charitable contributions and facilitated the emergence of popular philanthropy.