Abstract: Methods, systems, and apparatuses, including computer programs encoded on a computer storage medium, that rank items based on user interactions within the same web session. The method includes: providing a first content page for display on a client device; receiving a set of user interactions with one or more items of the first plurality of items; determining an affinity score representing a user interest in the attribute based on the set of user interactions; updating an attribute repository storing a second plurality of attributes and corresponding current affinity scores; identifying a second plurality of items and a corresponding third plurality of attributes; ranking the second plurality of items; and providing a second content page for display on the client device.