"We think of 'subscription' broadly," said Matt Darrow, VP and general manager of product at Zuora. "It's when companies do business with customers with whom they have a known relationship, and those relationships are sticky. The subscription model is great for engagement because companies know that in order to be successful they need to deliver ongoing services that keep providing value over and over again, because naturally clients can turn off their service and go somewhere else if they're not getting the outcome that they expect."