Feature scoring is a metric to measure the relevance, usability, and perception of application features from development through operations. It assigns a score to each feature based on how well it meets requirements, performs during testing, and is used in production. Elements factored into scoring include requirements, test results, bug reports, and usage telemetry. Features are prioritized using methods like MoSCoW and given weights based on criticality. Regular feature scoring supports prioritizing work and assessing the value added by each feature in both new and existing application development.