Identifying desirable experiences, then delivering them.
And a longer one from Harvard Business School:
Marketers concern themselves with acquiring and retaining customers, who are the lifeblood of an organization. They attract customers by learning about potential needs, helping to develop products that customers want, creating awareness, and communicating benefits; they retain them by ensuring that they get good value, appropriate service, and a stream of future products. The marketing function not only communicates to the customer, but also communicates the needs of the customer to the company. In addition, it arranges and monitors the distribution of products and/or services from company to customer.