Abstract: In general, the subject matter described in this specification can be embodied in methods, systems, and program products for providing a query to a search engine for searching a corpus of documents. A plurality of result documents are received from the search engine, each result document associated with a ranking. For a first document in the plurality, the following is performed. First, a second document in a second corpus is identified as containing content that identifies the same physical object as the first document. The second document was included in a plurality of result documents responsive to a second query of the second corpus, similar to the first query. Second, a new ranking is determined for the first document based on its ranking and relevance data associated with the second document. The relevance data is indicative of the second document's popularity as a result for the second query.

Abstract: Methods, systems, and apparatus, including computer program products are provided for responding to search queries having results that identify books. In one aspect, a search query and multiple web pages that satisfy the search query and have a ranked order as responses to the search query are received. A subset of web pages that are each a reference page for a respective book are selected. A web page is a reference page for a book when the web page includes a reference to the book and satisfies a citation criterion for the book. A book score is assigned to each of the books for which there is at least one reference page in the group of highest ranking web pages. The book scores are used to select one or more of the books. A book reference is generated for each of the books and the book references are provided in response to the search query.

Abstract: A system, method, and computer program determines section information of a digital volume. Digital volumes include digital representations of human-readable content, such as digitized books. Phrases are extracted from a table of contents of a digital volume. Matching phrases that at least approximately match the extracted phrases are identified in the body of the digital volume. A best matching phrase is determined for each extracted phrase based on the ordering of the extracted phrases and the matching phrases, and based on match scores indicating the quality of the matches. Section information is generated, including section headings and section start locations based on the best matching phrases. The digital volume is presented to users with links from the table of contents to the section headings on the section start pages. The section information is also used to enhance searching of the digital volume by users.

Abstract: A system identifies metadata associated with a document by capturing text of a document and comparing the text of the document with a collection of metadata records. Sets of matches between the text of the document and at least one record in the collection of metadata records may be identified, where each set of matches corresponds to a metadata record in the collection of metadata records. Metadata records corresponding to each set of matches may be scored. At least one of the metadata records may be identified based on the scores of the metadata records. The at least one identified metadata record may be associated with the document.

Abstract: Methods, systems, and apparatus, including computer program products, for generating user identifier profiles. A user identifier profile characterizes a user based on events that occurred during past user sessions for a user (e.g., past online activities). An event is an action that occurs during a user session, such as a web page view, an advertisement click-through, and a conversion. A user identifier profile can be used, for example, to select advertisements targeted to the user. A user identifier profile includes information about inferred user interests and inferred user demographics.

Abstract: A user is associated with profile information indicating a level of interest in a plurality of topic categories. To obtain an advertisement for a preferred category, the client requests advertisements data from two servers. A request to one of the ad servers includes a user preferred category and a number of other categories. A request to the other ad server includes only the other categories. After the servers send advertisements corresponding to the categories in the requests, a difference is determined between the received advertisements, which produces the advertisement for the preferred category. In some embodiments, a single request is made to a server for a number of advertisements, those advertisements corresponding to the user's profile information are provided a higher likelihood of display in accordance with the advertisement's similarity to the user's profile.

Abstract: In general, the subject matter described in this specification can be embodied in methods, systems, and program products for providing a query to a search engine for searching a corpus of documents. A plurality of result documents are received from the search engine, each result document associated with a ranking. For a first document in the plurality, the following is performed. First, a second document in a second corpus is identified as containing content that identifies the same physical object as the first document. The second document was included in a plurality of result documents responsive to a second query of the second corpus, similar to the first query. Second, a new ranking is determined for the first document based on its ranking and relevance data associated with the second document. The relevance data is indicative of the second document's popularity as a result for the second query.

Abstract: Methods, systems, and apparatus, including computer program products are provided for responding to search queries having results that identify books. In one aspect, a search query and multiple web pages that satisfy the search query and have a ranked order as responses to the search query are received. A subset of web pages that are each a reference page for a respective book are selected. A web page is a reference page for a book when the web page includes a reference to the book and satisfies a citation criterion for the book. A book score is assigned to each of the books for which there is at least one reference page in the group of highest ranking web pages. The book scores are used to select one or more of the books. A book reference is generated for each of the books and the book references are provided in response to the search query.

Abstract: Methods, systems, and apparatus, including computer program products, for generating user identifier profiles. A user identifier profile characterizes a user based on events that occurred during past user sessions for a user (e.g., past online activities). An event is an action that occurs during a user session, such as a web page view, an advertisement click-through, and a conversion. A user identifier profile can be used, for example, to select advertisements targeted to the user. A user identifier profile includes information about inferred user interests and inferred user demographics.

Abstract: Methods, systems, and apparatus for determining similarity measures between vertical categories based on users' online activities. The similarity measures are symmetric similarity measures based on both a similarity measure of a first vertical category relative to a second vertical category and a similarity measure of the second vertical category relative to the first vertical category.

Abstract: Methods, systems, and apparatus for determining similarity measures between vertical categories based on users' online activities. The similarity measures are symmetric similarity measures based on both a similarity measure of a first vertical category relative to a second vertical category and a similarity measure of the second vertical category relative to the first vertical category.

Abstract: Systems, methods, and computer program products for automating local content are described. In some implementations, an ad manager and a business table can be provided by a backend system. The business table can store, for example, user information, user account information including billing information, campaign related information and advertisement data associated with one or more local business advertisers as well as geo-targeting information. Based on the information stored in the business table, the ad manager can tailor a specific online advertising campaign on behalf of a local business advertiser. Where new or updated information is found, the ad manager can initiate campaign management updates to one or more business ad listings associated with the local business advertiser.

Abstract: Methods, systems, and apparatus, including computer program products, for generating user identifier profiles. A user identifier profile characterizes a user based on events that occurred during past user sessions for a user (e.g., past online activities). An event is an action that occurs during a user session, such as a web page view, an advertisement click-through, and a conversion. A user identifier profile can be used, for example, to select advertisements targeted to the user. A user identifier profile includes information about inferred user interests and inferred user demographics.

Abstract: A user interface (e.g., a browser window) includes a display area for displaying an image (e.g., a book page image). The image can be rescaled based on the dimensions of the display area, one or more attributes of the image and other factors. In some implementations, a sequence of images are searched for a table of contents. If a table of contents does not exist, one is created by searching the images for white space and/or other attributes that can be used to determined entries in the table of contents. The entries in the table of contents can be hypertext links.

Abstract: A user interface (e.g., a browser window) includes a display area for displaying a content reference page. In some implementations, a content reference page is generated that includes information related to content. The content reference page includes sections for presenting keywords found in the content, reviews of the content, portions of content that are of interest to a user (or a class of users) and other useful references, etc.

Abstract: A user interface (e.g., a browser window) includes a display area for displaying a content reference page. In some implementations, a content reference page is generated that includes information related to content. The content reference page includes sections for presenting keywords found in the content, reviews of the content, portions of content that are of interest to a user (or a class of users) and other useful references, etc.

Abstract: Among other disclosed subject matter, a computer-implemented method for characterizing user information includes receiving a plurality of identifiers associated with respective users. The method includes identifying, using the plurality of identifiers, any information portions in an information collection relating to at least one of the users, the information collection reflecting network activities by the users. The method includes generating a record that includes the plurality of identifiers associated with the corresponding information portions. The method includes identifying at least one of the information portions as corresponding to a category established for user classification. The method includes identifying a subset of the plurality of identifiers as associated with the category; and.

Abstract: Methods and systems allow users to enter natural language terms that describe a particular web site into an address field of a browser instead of a formal URL. The terms are evaluated to determine whether they correspond, with a high likelihood, to a particular web site. If so, this web site may be immediately accessed. If not, a list of search results based on the terms may be displayed by the browser.

Abstract: Methods and systems allow users to enter natural language terms that describe a particular web site into an address field of a browser instead of a formal URL. The terms are evaluated to determine whether they correspond, with a high likelihood, to a particular web site. If so, this web site may be immediately accessed. If not, a list of search results based on the terms may be displayed by the browser.

Abstract: Methods and systems allow users to enter natural language terms that describe a particular web site into an address field of a browser instead of a formal URL. The terms are evaluated to determine whether they correspond, with a high likelihood, to a particular web site. If so, this web site may be immediately accessed. If not, a list of search results based on the terms may be displayed by the browser.