10. A tangible computer readable storage medium comprising instructions that, when executed, cause a machine to at least: sort a set of messages based on a set of probabilities, the set of probabilities indicating a likelihood that the set of messages belong to a first classification; assign a first subset of first consecutive ones of the sorted set of messages to a first bucket; assign a second subset of second consecutive ones of the sorted set of messages to a second bucket, wherein a first message of the second bucket is consecutive to a last message of the first bucket with reference to the set of probabilities; determine a mean of probabilities of the first subset of messages assigned to the first bucket; store the mean in a tangible memory; store, for respective ones of the messages assigned to the first bucket, an indication that the respective message is assigned to the first bucket in the tangible memory, repeatedly (1) move a boundary between the first bucket and the second bucket and (2) recalculate the mean of probabilities of messages assigned to the first bucket in response to moving the boundary until deviations of the probabilities within the first bucket with respect to the mean are equal to or less than a threshold; and store a last recalculated mean as representative of the first bucket.
11. The tangible computer readable storage medium as defined in claim 10 , wherein the mean is a first mean, and further comprising determining a second mean of messages assigned to the second bucket and storing the second mean in the tangible memory.