What are the different fields of study in data mining?

I would roughly define the different application areas as

1) Clustering (unsupervised learning) e.g., to find groups of customers based on some similarity

2) Predictive modeling (supervised learning) 2.1) Classification e.g., medical diagnosis (sick/healthy), image classification etc. 2.2) Regression e.g., stock trade change prediction 2.3) Ranking e.g., search engine results

3) Association rule mining e.g., which products do customers frequently buy together

4) Anomaly detection e.g., credit fraud detection