We test the hypothesis that the Internet is a useful technology for controlling corruption. In order to do so, we develop a novel identification strategy for Internet diffusion. Power disruptions damage digital equipment, which increases the user cost of IT capital, and thus lowers the speed of Internet diffusion. A natural phenomenon causing power disruptions is lightning activity, which makes lightning a viable instrument for Internet diffusion. Using ground-based lightning detection censors as well as global satellite data, we construct lightning density data for the contiguous U.S. states and a large cross section of countries. Empirically, lightning density is a strong instrument for Internet diffusion and our IV estimates suggest that the emergence of the Internet has served to reduce the extent of corruption across U.S. states and across the world.