A local election comes down to a few hundred votes. Yard signs are everywhere, the town hall is half empty-and the real campaign is unfolding in newsfeeds and recommendation widgets that no one in the room designed or voted for. Civic life now runs through systems built to maximize engagement and advertising revenue. Yet many people who care about democracy, local news, or public debate still treat the details of platform design, ranking, and targeting as a black box. Evan K. Marshall opens that box. With clear examples and a reporter's eye for incentives, he traces how social platforms and large AI models earn money, decide what to amplify, and quietly redefine what counts as "relevant" to you as a citizen. Chapter by chapter, he follows the chain from business model to newsfeed to ballot box: political ads and microtargeting, elections conducted under private platform rules, the hollowing out of local journalism, impossible content moderation workloads, and the flood of AI-generated posts and images. Instead of outrage or easy optimism, Marshall offers a grounded way to think about your own role in this environment. He highlights practical steps that individuals, communities, and local governments can take to reduce harms, support trustworthy information, and rebuild civic resilience-without becoming full-time activists or engineers. For readers who follow technology and politics but want fewer hot takes and more usable insight, Civic Sense in a Digital Age provides a calm, evidence-informed map of the digital systems shaping public life and what can still be done about them.