Abstract: A system may track statistics for a number of features using an approximate counting technique by: subjecting each feature to multiple, different hash functions to generate multiple, different hash values, where each of the hash values may identify a particular location in a memory, and storing statistics for each feature at the particular locations identified by the hash values. The system may generate rules for a model based on the tracked statistics.

Abstract: A system may determine an extent to which a document is selected when the document is included in a set of search results, generate a score for the document based, at least in part, on the extent to which the document is selected when the document is included in a set of search results; and rank the document with regard to at least one other document based, at least in part, on the score.

Abstract: A system may determine an extent to which a document is selected when the document is included in a set of search results, generate a score for the document based, at least in part, on the extent to which the document is selected when the document is included in a set of search results; and rank the document with regard to at least one other document based, at least in part, on the score.

Abstract: A system may determine an extent to which a document is selected when the document is included in a set of search results, generate a score for the document based, at least in part, on the extent to which the document is selected when the document is included in a set of search results; and rank the document with regard to at least one other document based, at least in part, on the score.

Abstract: A system may determine a measure of how a content of a document changes over time, generate a score for the document based, at least in part, on the measure of how the content of the document changes over time, and rank the document with regard to at least one other document based, at least in part, on the score.

Abstract: Systems and methods that improve search rankings for a search query by using data associated with queries related to the search query are described. In one aspect, a search query is received, a related query related to the search query is determined, an article (such as a web page) associated with the search query is determined, and a ranking score for the article based at least in part on data associated with the related query is determined. Several algorithms and types of data associated with related queries useful in carrying out such systems and methods are described.

Abstract: A system may determine an extent to which a document is selected when the document is included in a set of search results, generate a score for the document based, at least in part, on the extent to which the document is selected when the document is included in a set of search results; and rank the document with regard to at least one other document based, at least in part, on the score.

Abstract: A stopword detection component detects stopwords (also stop-phrases) in search queries input to keyword-based information retrieval systems. Potential stopwords are initially identified by comparing the terms in the search query to a list of known stopwords. Context data is then retrieved based on the search query and the identified stopwords. In one implementation, the context data includes documents retrieved from a document index. In another implementation, the context data includes categories relevant to the search query. Sets of retrieved context data are compared to one another to determine if they are substantially similar. If the sets of context data are substantially similar, this fact may be used to infer that the removal of the potential stopword(s) is not material to the search. If the sets of context data are not substantially similar, the potential stopword can be considered material to the search and should not be removed from the query.

Abstract: A similarity detector detects similar or near duplicate occurrences of a document. The similarity detector determines similarity of documents by characterizing the documents as clusters each made up of a set of term entries, such as pairs of terms. A pair of terms, for example, indicates that the first term of the pair occurs before the second term of the pair in the underlying document. Another document that has a threshold level of term entries in common with a cluster is considered similar to the document characterized by the cluster.

Abstract: A system for generating a model is provided. The system generates, or selects, candidate conditions and generates, or otherwise obtains, statistics regarding the candidate conditions. The system also forms rules based, at least in part, on the statistics and the candidate conditions and selectively adds the rules to the model.

Abstract: A system may determine an extent to which a document is selected when the document is included in a set of search results, generate a score for the document based, at least in part, on the extent to which the document is selected when the document is included in a set of search results; and rank the document with regard to at least one other document based, at least in part, on the score.

Abstract: A learning model is built on a combination of advertiser, publisher and user data. The learning model can be applied to all advertisers in an advertising system. The learning model provides predicted conversion rates for a given advertisement (“ad”) appearing on different publisher networks. A predicted conversion rate represents the probability that a click on a given ad appearing on a given publisher will lead to a conversion. The predicted conversion rates are used to generate a multiplier. The multiplier is used to automatically adjust the advertiser's bid (e.g., maximum cost-per-click (CPC)) for the given ad prior to an auction for the ad. Adjusting the advertiser's bid equalizes a cost-per-conversion among the publishers for the ad.

Abstract: Systems and methods that improve search rankings for a search query by using data associated with queries related to the search query are described. In one aspect, a search query is received, a population associated with the search query is determined, an article (such as a webpage) associated with the search query is determined, and a ranking score for the article based at least in part on data associated with the population is determined. Algorithms and types of data associated with a population useful in carrying out such systems and methods are described.

Abstract: Systems and methods that improve search rankings for a search query by using data associated with queries related to the search query are described. In one aspect, a search query is received, a population associated with the search query is determined, an article (such as a webpage) associated with the search query is determined, and a ranking score for the article based at least in part on data associated with the population is determined. Algorithms and types of data associated with a population useful in carrying out such systems and methods are described.

Abstract: A system automatically creates a list from items in existing lists. The system receives one or more example items corresponding to the list and assigns weights to the items in the existing lists based on the one or more example items. The system then forms the list based on the items and the weights assigned to the items.

Abstract: A system may determine a measure of how a content of a document changes over time, generate a score for the document based, at least in part, on the measure of how the content of the document changes over time, and rank the document with regard to at least one other document based, at least in part, on the score.

Abstract: A system may determine an extent to which a document is selected when the document is included in a set of search results, generate a score for the document based, at least in part, on the extent to which the document is selected when the document is included in a set of search results; and rank the document with regard to at least one other document based, at least in part, on the score.

Abstract: A system may determine an extent to which a document is selected when the document is included in a set of search results, generate a score for the document based, at least in part, on the extent to which the document is selected when the document is included in a set of search results; and rank the document with regard to at least one other document based, at least in part, on the score.

Abstract: A system may determine an extent to which a document is selected when the document is included in a set of search results, generate a score for the document based, at least in part, on the extent to which the document is selected when the document is included in a set of search results; and rank the document with regard to at least one other document based, at least in part, on the score.

Abstract: A system may determine an extent to which a document is selected when the document is included in a set of search results, generate a score for the document based, at least in part, on the extent to which the document is selected when the document is included in a set of search results; and rank the document with regard to at least one other document based, at least in part, on the score.