An interactive D3.js dashboard analyzing revenue, churn, and customer segments for a telecom subscription business (7,043 real customers). Calculates "Revenue at Risk" turning a churn rate into a churn cost and finds that contract type is the strongest churn predictor (42.7% for month-to-month vs. 2.8% for two-year contracts), while payment method is a surprisingly strong signal on its own: electronic check users churn at 45.3%, nearly 3x automatic payment methods.