5. A system, comprising: at least one computing device comprising a processor and a memory; and an application stored in the memory and comprising instructions executable by the processor of the at least one computing device, wherein the application, when executed, causes the at least one computing device to at least: access a catalog that organizes a plurality of items into a categorical hierarchy, wherein each item is expressed in terms of a product description; parse at least a portion of the product descriptions associated with a selected category to generate a plurality of keywords for the selected category; select a subset of the plurality of keywords; generate at least one rule based on the subset, wherein an application of the at least one rule specifies a respective binary result depending upon whether the subset of the plurality of keywords is included in a prospective seller product description; apply the at least one rule to the prospective seller product description to determine that the prospective seller product description expresses an item within the selected category; calculate a percentage of a plurality of product descriptions correctly categorized with the at least one rule; and update the at least one rule based at least in part on the calculated percentage.
5. A system, comprising: at least one computing device comprising a processor and a memory; and an application stored in the memory and comprising instructions executable by the processor of the at least one computing device, wherein the application, when executed, causes the at least one computing device to at least: access a catalog that organizes a plurality of items into a categorical hierarchy, wherein each item is expressed in terms of a product description; parse at least a portion of the product descriptions associated with a selected category to generate a plurality of keywords for the selected category; select a subset of the plurality of keywords; generate at least one rule based on the subset, wherein an application of the at least one rule specifies a respective binary result depending upon whether the subset of the plurality of keywords is included in a prospective seller product description; apply the at least one rule to the prospective seller product description to determine that the prospective seller product description expresses an item within the selected category; calculate a percentage of a plurality of product descriptions correctly categorized with the at least one rule; and update the at least one rule based at least in part on the calculated percentage. 6. The system of claim 5 , wherein causing the at least one computing device to select the subset of the plurality of keywords further comprises causing the at least one computing device to select a predetermined number of search terms.