Data mining has two complementary goals: understanding and prediction. It encompases many technologies and techniques from AI, physics, statistics, and machine learning.
Data mining operates on observational, secondary, or retrospective data. This is not data gathered for an experiment, but is often recorded for other purposes and is cheap to obtain.
There are common types or sources of data that have similar properties e.g. web data or streaming data.
Exploratory Data Analysis Data Visualization Dimensionality reduction Clustering Pattern detection and anomaly detection
The stuff that makes money
Classification Ranking Regression Matrix completion (recommender systems)