Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for receiving a search query from a client device; receiving search result data identifying a first plurality of search result resources and respective initial scores for each of the first plurality of search result resources; identifying a respective group of resources to which each of the search result resources belongs; determining a respective group-based modification factor for each group of resources; and adjusting the initial score for each of the search result resources based at least in part on the group-specific modification factor for the group of resources to which the search result resource belongs to generate a respective second score for each of the search result resources.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for predicating a measure of quality for a site, e.g., a web site. In some implementations, the methods include obtaining baseline site quality scores for multiple previously scored sites; generating a phrase model for multiple sites including the previously scored sites, wherein the phrase model defines a mapping from phrase specific relative frequency measures to phrase specific baseline site quality scores; for a new site that is not one of the previously scored sites, obtaining a relative frequency measure for each of a plurality of phrases in the new site; determining an aggregate site quality score for the new site from the phrase model using the relative frequency measures of phrases in the new site; and determining a predicted site quality score for the new site from the aggregate site quality score.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for determining a first count of unique queries, received by a search engine, that are categorized as referring to a particular site; determining a second count of unique queries, received by the search engine, that are associated with the particular site, wherein a query is associated with the particular site when the query is followed by a user selection of a search result that (a) was presented, by the search engine, in response to the query and (b) identifies a resource in the particular site; and determining, based on the first and second counts, a site quality score for the particular site.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for receiving a search query from a client device; receiving search result data identifying a first plurality of search result resources and respective initial scores for each of the first plurality of search result resources; identifying a respective group of resources to which each of the search result resources belongs; determining a respective group-based modification factor for each group of resources; and adjusting the initial score for each of the search result resources based at least in part on the group-specific modification factor for the group of resources to which the search result resource belongs to generate a respective second score for each of the search result resources.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for determining duration performance of websites. In one aspect, a method includes, for each website of a plurality of websites: obtaining duration measurements of user device visits to resources of the website for a plurality of different users, obtaining data describing a plurality of categories to which the website belongs; determining, for each category of the plurality of categories to which the website belongs, a category duration score for the category based on the website duration score for the website; and determining, from one or more of the category duration scores, a duration performance score for the website.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for revising search queries. One of the methods includes receiving an original search query submitted by a user of a user device; determining that the original search query is similar to a first search query of a plurality of search queries previously submitted by the user; selecting a first term that appears in the first search query and not in the original search query, wherein selecting the first term comprises determining that the first term appears in at least a threshold number of other distinct search queries of the plurality of search queries previously submitted by the user; generating a revised search query by adding the first term that appears in the first search query to the original search query; and obtaining search results for the revised search query from a search engine.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for servicing search queries. In one aspect, a method includes determining that a general search query is a locally significant query for a user location that is associated with the user general search query. In turn, a local search query is generated using the general search query and a location phrase representing the user location. A set of set of general search results responsive to the general search query and a set of local search results responsive to the local search query are requested. A final set of search results responsive to the search query are selected. The final set of search results include at least one search result that is included in the set of local search results, and is not included in a pre-specified quantity of highest ranking search results from the set of general search results. Data that cause presentation of the final set of search results are provided.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for determining duration performance of websites. In one aspect, a method includes, for each of a plurality of websites, obtaining duration measurements of user device session visits to resources of the website, obtaining data describing a plurality of categories to which the website belongs; determining for each of the plurality of categories to which the website belongs, a category duration score based on the duration measurements, each category durations score being proportional to durations of time from the duration measurements; and determining from one or more of the category duration scores, a duration performance score for the website, the duration performance score proportional to the one or more category duration scores from which the duration performance score is determined.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for obtaining search results from high-quality sites. One of the methods includes receiving data identifying first resources that are responsive to a first query. If at least a first threshold number N of top-ranked first resources are located on sites previously identified as low quality sites, a second query and data identifying second resources that are responsive to the second query are obtained, wherein at least a second threshold number M of top-ranked second resources are located on sites previously identified as being high-quality sites. Search results are provided in response to the first query, wherein the search results identify one or more of the first resources and also identify a particular second resource of the second resources.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for determining a first count of unique queries, received by a search engine, that are categorized as referring to a particular site; determining a second count of unique queries, received by the search engine, that are associated with the particular site, wherein a query is associated with the particular site when the query is followed by a user selection of a search result that (a) was presented, by the search engine, in response to the query and (b) identifies a resource in the particular site; and determining, based on the first and second counts, a site quality score for the particular site.

Abstract: Methods and apparatus to generate templates from web images for searching an image database are described. In one embodiment, one or more retrieved images (e.g., from the Web) may be used to generate one or more templates. The templates may be used to search an image database based on features commonly shared between sub-images of the retrieved images. Other embodiments are also described.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for predicating a measure of quality for a site, e.g., a web site. In some implementations, the methods include obtaining baseline site quality scores for multiple previously scored sites; generating a phrase model for multiple sites including the previously scored sites, wherein the phrase model defines a mapping from phrase specific relative frequency measures to phrase specific baseline site quality scores; for a new site that is not one of the previously scored sites, obtaining a relative frequency measure for each of a plurality of phrases in the new site; determining an aggregate site quality score for the new site from the phrase model using the relative frequency measures of phrases in the new site; and determining a predicted site quality score for the new site from the aggregate site quality score.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for servicing search queries. In one aspect, a method includes determining that a general search query is a locally significant query for a user location that is associated with the user general search query. In turn, a local search query is generated using the general search query and a location phrase representing the user location. A set of set of general search results responsive to the general search query and a set of local search results responsive to the local search query are requested. A final set of search results responsive to the search query are selected. The final set of search results include at least one search result that is included in the set of local search results, and is not included in a pre-specified quantity of highest ranking search results from the set of general search results. Data that cause presentation of the final set of search results are provided.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for ranking search results. One of the methods includes determining, for each of a plurality of groups of resources, a respective count of independent incoming links to resources in the group; determining, for each of the plurality of groups of resources, a respective count of reference queries; determining, for each of the plurality of groups of resources, a respective group-specific modification factor, wherein the group-specific modification factor for each group is based on the count of independent links and the count of reference queries for the group; and associating, with each of the plurality of groups of resources, the respective group-specific modification factor for the group, wherein the respective group-specific modification for the group modifies initial scores generated for resources in the group in response to received search queries.

Abstract: Methods and apparatus to generate templates from web images for searching an image database are described. In one embodiment, one or more retrieved images (e.g., from the Web) may be used to generate one or more templates. The templates may be used to search an image database based on features commonly shared between sub-images of the retrieved images. Other embodiments are also described.