15. A non-transitory computer-readable medium storing a set of instructions executable by a processor to: provide a candidate category hierarchy, including candidate categories, and a mapping between reference pages and the candidate categories, including mapped reference pages; obtain population usage data of each of the mapped reference pages; use the population usage data to determine a population traffic metric for each of the candidate categories; generate population categories from the candidate categories by using the population traffic metric of each of the candidate categories; produce a population category hierarchy including the population categories; and modify the mapping to create a population mapping, wherein the mapped reference pages are re-mapped to the population categories to create the population mapping.
15. A non-transitory computer-readable medium storing a set of instructions executable by a processor to: provide a candidate category hierarchy, including candidate categories, and a mapping between reference pages and the candidate categories, including mapped reference pages; obtain population usage data of each of the mapped reference pages; use the population usage data to determine a population traffic metric for each of the candidate categories; generate population categories from the candidate categories by using the population traffic metric of each of the candidate categories; produce a population category hierarchy including the population categories; and modify the mapping to create a population mapping, wherein the mapped reference pages are re-mapped to the population categories to create the population mapping. 17. The non-transitory computer-readable medium of claim 15 , wherein the instructions to modify the mapping further include instructions to: use relevance metrics for each of the population categories to identify a relevance level for each of the population categories and the mapped reference pages; and re-map the mapped reference pages according to the relevance level of each of the population categories.