The rapid growth in computing power and storage has led to progressively more data being collected. Big datasets are certainly large and complex, but in order to fully define ‘big data’ we need first to understand ‘small data’ and its role in statistical analysis. ‘Why is big data special?’ considers the four main characteristics of big data: volume, variety, velocity, and veracity, which present a considerable challenge in data management. The advantages we expect to gain from meeting this challenge and the questions we hope to answer with big data can be understood through data mining. The use of big data mining in credit card fraud detection is discussed.