1. A method for training a hierarchical classifier for classification of documents into a classification hierarchy, the method comprising: providing training data for training the classifiers, the training data including documents and classifications of the documents within the classification hierarchy; for each classifier for a classification within the classification hierarchy, identifying one of a plurality of agents to train the classifier so that multiple agents train different classifiers; and under control of the identified agent, training the classifier wherein the classifiers trained by the multiple agents form the hierarchical classifier.