1. A method for automatically detecting and categorizing topics in a plurality of interactions between customers and agents of a contact center during one or more time periods, the interactions comprising a plurality of phrases, the method comprising: extracting a plurality of fragments from the plurality of interactions in accordance with one or more extraction rules by a processor of an analytics system configured to automatically detect and categorize topics in the plurality of interactions, at least one of the extraction rules comprising a part of speech sequence, the extraction rules being automatically generated based on a set of key fragments; filtering, by the processor, the plurality of fragments to generate a filtered plurality of fragments; clustering, by the processor, the filtered fragments into a plurality of base clusters; clustering, by the processor, the plurality of base clusters into a plurality of hyper clusters; and outputting, by the processor, a hierarchy of concepts in accordance with the filtered fragments clustered into the base clusters and the base clusters clustered into the hyper clusters, the base clusters corresponding to topics detected in the interactions occurring during the one or more time periods, and the hyper clusters corresponding to categorizations of the topics.