9. The method of claim 1 , wherein determining the one or more relationships comprises determining that the first product and the second product are alternatives based on the content of the unstructured text; and including the first product and the second product in the cluster of similar products occurs in response to determining that the first product and the second product are alternatives.
1. A method comprising: providing a document that includes a navigational tool configured to permit navigation among hierarchical categories of products, the navigational tool presenting a first set of sub-categories each corresponding to a different cluster of products; identifying unstructured text of one or more consumer-submitted comments in a document associated with a first product; identifying, in the unstructured text of the one or more consumer-submitted comments, a reference to a second product different from the first product; determining one or more relationships between the first product and the second product based on content of the unstructured text of the one or more consumer-submitted comments; in response to determining the one or more relationships between the first product and the second product, including the first product and the second product in a cluster of related products; in response to determining the one or more relationships between the first product and the second product, changing the first set of sub-categories to generate a second set of sub-categories different from the first set of sub-categories, the second set of sub-categories comprising a sub-category that corresponds to the cluster that includes the first product and the second product; and after changing the first set of sub-categories, providing the document that includes the navigational tool such that the navigational tool presents the second set of sub-categories, wherein each of the above are performed by one or more processing devices.