The Denver Center for the Performing Arts cut its email list by 30 percent and turned up their ROI by 738 percent. The company cut 220,000 names from its list of 550,000 email subscribers and began sending more targeted emails based on the customer's demographic and purchase history. In addition, the company counted a 210 percent increase in click through rates, 95 percent decrease in opt-outs and a 90 percent decrease in spam complaints.