A content server monitors media preferences of a user associated with a partial user profile specifying partial demographic information about the user. The content server deconstructs the monitored media preferences to identify preferences of the user for musicological features of the media items. The content server infers profile information missing from the partial user profile responsive to the preferences of the user for musicological features of the media items, the inferring using baseline information associating profile information of a plurality of baseline users with preferences for musicological features of media items. The content server selects an advertisement using the inferred profile information, and provides the selected advertisement to a client device used by the user.