1. A network device to manage a delivery of a message over a network, comprising: a transceiver to send and receive data over a network; and a processor that is operative to perform actions, comprising: performing a first pass analysis on a plurality of messages, which have been previously sorted into a plurality of different message folders by a first message filter, using a second, multi-pass message filter that is configured to generate a classification model based on the first pass analysis, wherein the generated classification model is configured to reside exclusively in a non-persistent memory location; using the generated classification model with the second, multi-pass message filter to perform a second pass on the sorted plurality of messages, to generate a misclassification identification of sorted messages; displaying the misclassification identification of sorted messages such that at least one misclassified message can be moved to a different message folder based on the misclassification identification; and purging the generated classification model from non-persistent memory location.