This article provides a detailed analysis of rural Kenyan women and their interactions with the products and services of Safaricom Ltd., Kenya's dominant mobile network provider. The amplification theory of technology offers a framework for analyzing our data, and we find that differential motivation and capacity are mechanisms that appear to benefit the network provider, while disadvantaging rural mobile phone owners. In particular, the design of Safaricom's airtime scratch cards and mobile services does not support rural users' capabilities. Our analysis suggests that technologists consider their ongoing responsibilities for technologies they built yesterday-that is, they should address problems inherent in the current design of mobile-phone interfaces. We offer practical recommendations on how to do this, and ask HCI/ICTD researchers and practitioners to more carefully consider how overlooking corporate power structures and their impact on mobile phone use amplifies social inequality.