1. A method of assisting users in locating items that are arranged within a database system by category, the method comprising: monitoring user actions performed with respect to specific items in the database system to generate item usage data; calculating item scores for specific items in the database system, wherein an item score for an item is dependent upon the item usage data associated with that item; receiving a search query specified by a user; identifying, within each of multiple categories of the database system, items that are responsive to the search query (“responsive items”); for each of the multiple categories, calculating a respective category score based at least in-part on the item scores of responsive items in that category; and determining an order in which to present the multiple categories to the user such that the order is dependent upon the category scores.