9. The method of claim 1 , further comprising: determining at least one semantic parameter within the first clause using at least one linguistic analysis rule based on parts of speech roles of the words in the clause; and computing the impact of the first clause of the at least one cluster with respect to the at least one category using the at least one semantic parameter.
10. The method of claim 9 wherein the at least one semantic parameter comprises at least one of: a representative concept of the document, an impact phrase, an intensity corresponding to the impact phrase, object, subject, time-period corresponding to the impact phrase and a location and is not related to frequency or word patterns.