24. The system of claim 23 , wherein the classifier is a transductive classifier, and further comprising training the transductive classifier through iterative calculation using at least one predetermined cost factor, the search query, and the documents, wherein for each iteration of the calculations the cost factor is adjusted as a function of an expected label value, and using the trained classifier to classify the documents.
24. The system of claim 23 , wherein the classifier is a transductive classifier, and further comprising training the transductive classifier through iterative calculation using at least one predetermined cost factor, the search query, and the documents, wherein for each iteration of the calculations the cost factor is adjusted as a function of an expected label value, and using the trained classifier to classify the documents. 25. The system of claim 24 , further comprising receiving a data point label prior probability for the search query and documents, wherein for each iteration of the calculations the data point label prior probability is adjusted according to an estimate of a data point class membership probability.