1. A method of assisting a user in locating products while browsing an online catalog of products, comprising, during a browsing session: maintaining a history of products viewed by the user during the browsing session (“viewed products”); selecting a set of additional products to present to the user based on the history of viewed products, wherein a product is selected to include in the list of additional products based at least in part on whether that product is related to more than one of the viewed products; outputting to the user the list of the additional products and a list of the viewed products; and presenting to the user an option to individually de-select the viewed products and to thereafter view a refined set of additional products which reflects de-selection of one or more of the viewed products.