1. A method, comprising: obtaining source or destination information from a data packet; comparing data within the data packet to one or more keywords, the keywords are associated with a common subject of interest; establishing a number of times in which one of the keywords matches at least a portion of the data; ranking an interest in the common subject in part based on the established number of matches; and defining a user interest vector that correlates the source or destination information, the common subject and the ranked interest.