14. The system of claim 13 , wherein the alert is generated when the topic intensity for one topic reaches a threshold level or changes at a threshold rate.
14. The system of claim 13 , wherein the alert is generated when the topic intensity for one topic reaches a threshold level or changes at a threshold rate. 16. The system of claim 14 , wherein: the threshold level includes an automatically generated threshold level based on one or more stored topic intensities; and the threshold rate includes an automatically generated threshold rate based on one or more stored topic intensities.