1. One or more computer storage media having computer executable instructions embodied thereon that is executed by a processing unit for performing a method for facilitating document classification, the method comprising: receiving a plurality of documents, each document having text associated therewith; pre-classifying each of the plurality of documents into one or more pre-defined classes of a hierarchical structure, wherein the hierarchical structure arranges the one or more predefined classes into a single root class and lower level classes; parsing the text associated with each document into one or more features, wherein at least one of the one or more features includes a plurality of terms; determining a frequency of occurrence of the one or more features parsed from the text associated with each document; identifying those features that are associated with a determined frequency of occurrence that meets or exceeds a threshold frequency as preliminary indefinite features; counting documents within the plurality of documents that are associated with the features identified as preliminary indefinite features; ascertaining that the count of the documents meets or exceeds a document threshold; and storing the identified features that occur in the text associated with the documents as vocabularies associated with a predefined class of the one or more predefined classes, wherein the vocabularies are unique to each of the one or predefined classes at a same equivalence level of the lower level classes of the hierarchical structure, and wherein the identified features are stored as vocabularies of the lower level classes related by a branch connection to the predefined class associated with the stored vocabularies.