Societal-scale software systems, such as today's commercial social media platforms, are among the most widely used software systems in the world, with some platforms reporting billions of daily active users. These systems have created new mechanisms for global communication and connect people with unprecedented speed. Despite the numerous benefits of societal-scale systems, these systems are designed to optimize user engagement and scale by using psychology (such as gaming and reward mechanisms) to influence users. Individual users struggle with privacy of their data and bias in these systems, while governments face new threats of misinformation. In this podcast from the Carnegie Mellon University Software Engineering Institute, John Robert and Forrest Shull discuss issues that must be considered when engineering societal-scale systems.