1. A method of using a user model with salience, the method comprising: providing a content item to a user through a user interface; receiving physiological data corresponding to a physiological response of the user as the user interacts with the content item provided through the user interface; determining a salience score for the content item based at least in part on the physiological response of the user; updating a user model with the salience score for the content item; determining a salience ranking for one or more keywords of the content item based on the salience score for the content item; determining a relevance ranking for the one or more keywords of the content item based on the relevance of the one or more keywords to the content item; and updating the user model to include a combined score for the one or more keywords of the content item based on the salience ranking and the relevance ranking; wherein the salience ranking is at least partially based on the timing of determining the salience score for the content item.