9. A non-transitory computer-readable storage medium encoded with a computer program comprising instructions that, when executed, operate to cause a computer to perform operations comprising: receiving a search query comprising one or more query terms and one or more labels; obtaining a plurality of search results responsive to the query terms, wherein each of the search results has a respective score and a respective uniform resource locator, and wherein the plurality of search results are ranked according to the respective scores; identifying one or more different domains from a plurality of uniform resource locator patterns associated with the labels; selecting a highest ranked plurality of first search results from the plurality of search results wherein a threshold number of the selected first search results have respective uniform resource locators that contain one of the identified domains; annotating each first search result of a plurality of the first search results with one or more of the labels that are associated with uniform resource locator patterns that match the respective uniform resource locator of the first search result; modifying the respective score of one or more of the annotated first search results wherein modifying the score of the annotated first search result comprises adjusting the score by a weight associated with a label annotation of the annotated first search result; ranking the annotated first search results based on the one or more modified scores; and providing the ranked annotated first search results as a response to the search query.
9. A non-transitory computer-readable storage medium encoded with a computer program comprising instructions that, when executed, operate to cause a computer to perform operations comprising: receiving a search query comprising one or more query terms and one or more labels; obtaining a plurality of search results responsive to the query terms, wherein each of the search results has a respective score and a respective uniform resource locator, and wherein the plurality of search results are ranked according to the respective scores; identifying one or more different domains from a plurality of uniform resource locator patterns associated with the labels; selecting a highest ranked plurality of first search results from the plurality of search results wherein a threshold number of the selected first search results have respective uniform resource locators that contain one of the identified domains; annotating each first search result of a plurality of the first search results with one or more of the labels that are associated with uniform resource locator patterns that match the respective uniform resource locator of the first search result; modifying the respective score of one or more of the annotated first search results wherein modifying the score of the annotated first search result comprises adjusting the score by a weight associated with a label annotation of the annotated first search result; ranking the annotated first search results based on the one or more modified scores; and providing the ranked annotated first search results as a response to the search query. 12. The non-transitory computer-readable storage medium of claim 9 wherein selecting the highest ranked plurality of first search results from the plurality of search results uses a Bloom filter that represents the one or more different domains.