While most people think of marketing as a tool to generate new customers, it is also a tool used to engage, retain, and up-sell or cross-sell to current customers. For example, in business with a recurring revenue model, such as a Software as a Service (SaaS) company, you make money each month or year off your customers. Think of Shopify (Links to Shopify: https://www.shopify.com/) as an example. How do you think they use big data in marketing to their current customers? Consider what information would allow them to profit more from their customers and any CRM and/or marketing automation tools that they might use to help them manage this process.