The ability to send out customized surveys, and then track the results. The ability to create different surveys, and track the results. I wish there was a way to customize the survey questions. I have used other survey tools, but Stacks Data is the best. It is easy to use, and the results are amazing. I have used Stacks Data to track customer satisfaction, and customer feedback. I have also used it to track employee satisfaction. I have also used it to track the amount of customers who have purchased a product.