1. A computer-implemented method comprising: (A) identifying a first plurality of documents associated with a user; (B) identifying a plurality of search strings based on a plurality of class keywords associated with a plurality of nodes in a taxonomy, the plurality of nodes being associated with a first plurality of classes; (C) identifying a second plurality of classes, in the taxonomy, associated with the first plurality of documents by performing a plurality of searches on the first plurality of documents using the identified plurality of search strings; and (D) associating the second plurality of classes with the user.