Discover Financial Services uses targeted email segmentation and testing provided by e-Dialog to improve customer engagement. By applying business rules to segment customers based on factors like credit card usage and website activity, and then testing different content with each segment, Discover has increased open rates by an average of 27%, click rates by 149%, while reducing unsubscribes by 67% over three years. This data-driven approach allows Discover to deliver personalized messages to customers at the right time to drive business results.