Abstract: As an example, a system includes a hierarchical tag database that includes a plurality of tags arranged according to a hierarchical data schema for a number of tag hierarchies, and tags within each level of a respective tag hierarchy have a different specificity relative to each other level of the respective tag hierarchy. The data can also include profile tag data for a given user. The system can also include a processor configured to access the media and execute the instructions to expand each of the stored profile tags for the given user to provide an expanded profile tag data set for the given user, in which the expanded profile tag data set includes each of the assigned profile tags and each one or more higher-level tag in each associated tag hierarchy to which each of the assigned profile tags belongs.