11. A computer-readable medium encoded with a computer program comprising instructions that, when executed, operate to cause a computer to perform operations comprising: receiving a search query over a network, the search query comprising a query term and a categorical identifier; selecting a domain name associated with the categorical identifier; generating, based on selecting a first result set of resources responsive to the query term, a second result set of resources in which a respective domain name for each resource matches the determined domain name associated with the categorical identifier; selecting a resource identifier associated with the categorical identifier, the selected resource identifier comprising the determined domain name and a path; enhancing a respective relevance score of each resource in the second result set whose respective resource identifier includes the selected resource identifier, a magnitude of enhancement being based on a weight associated with the categorical identifier, the respective relevance score indicating a degree of relevance between the resource and the query term; ranking each of the resources in the second result set based on the respective relevance scores; annotating, with the categorical identifier, one or more indicia identifying the resources of the ranked second result set whose respective resource identifier matches the selected resource identifier associated with the categorical identifier; and providing the annotated indicia over the network as a search engine result of the search query.
11. A computer-readable medium encoded with a computer program comprising instructions that, when executed, operate to cause a computer to perform operations comprising: receiving a search query over a network, the search query comprising a query term and a categorical identifier; selecting a domain name associated with the categorical identifier; generating, based on selecting a first result set of resources responsive to the query term, a second result set of resources in which a respective domain name for each resource matches the determined domain name associated with the categorical identifier; selecting a resource identifier associated with the categorical identifier, the selected resource identifier comprising the determined domain name and a path; enhancing a respective relevance score of each resource in the second result set whose respective resource identifier includes the selected resource identifier, a magnitude of enhancement being based on a weight associated with the categorical identifier, the respective relevance score indicating a degree of relevance between the resource and the query term; ranking each of the resources in the second result set based on the respective relevance scores; annotating, with the categorical identifier, one or more indicia identifying the resources of the ranked second result set whose respective resource identifier matches the selected resource identifier associated with the categorical identifier; and providing the annotated indicia over the network as a search engine result of the search query. 12. The computer-readable medium of claim 11 , further comprising: selecting other labels associated with the second result set of resources; and providing the selected other labels with the annotated indicia.