1. In a system, implemented by at least one processing device, based on a classification algorithm operating upon classifiable electronic data, a method for incorporating user input concerning classification of a plurality of data elements in the classifiable electronic data, the method comprising: calculating a first input-invariant part, independent of classification probabilities for the plurality of data elements, of the classification algorithm; receiving user input concerning classification of at least one data element of the plurality of data elements; modifying a first classification part of the classification algorithm based on the user input to provide a modified first classification part; and calculating a recalculated first classification part based on the modified first classification part and the first input-invariant part, wherein the recalculated first classification part comprises first classification probabilities for at least a portion of the plurality of data elements.