A customer journey map shows the story of the customer's experience. It not only identifies key interactions that the customer has with the organization, but it also brings user's feelings, motivations and questions for each of the touchpoints. Finally, a customer journey map has the objective of teaching organizations more about their customers.
Journey Mapping can be useful when you want to understand all of the steps a typical customer might go through, so you can find areas that need improvement. This can be very useful to help you innovate in an established industry.
You can read more about Journey Mapping as part of customer experience here.