For example, the average mutual information MI(g,u) between a gender user profile attribute and users for each web page considered by the classifier can be determined as follows: MI ??? ( g , u ) = ??? g ??? ??? u ??? P ??? ( g , s , u ) ??? log ??? P ??? ( g | s , u ) P ??? ( g ) [0104] For each gender, the N users with the largest MI values are selected, where N is an integer greater than 1. [01