The SPM Salford Predictive Modeler software suite offers several tools for clustering and segmentation including CART, Random Forests, and a classical statistical module CLUSTER. In this article we illustrate the use of these tools with the well known Boston Housing data set (pertaining to 1970s housing prices and neighborhood characteristics in the greater Boston area).
CART in its classification role is an excellent example of "supervised" learning: you cannot start a CART classification analysis without first selecting a target or dependent variable. All partitioning of the data into homogeneous segments is guided by the primary objective of separating the target classes. If the terminal nodes are sufficiently pure in a single target class the analysis will be considered successful even if two or more terminal nodes are very similar on most predictor variables.