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, 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 method of determining charge for content presentation includes identifying multiple target criteria that a content provider specifies for distribution of content, the multiple target criteria associated in a hierarchy. The method includes determining, for a presentation of the content to a user, which of the multiple target criteria are met by the presentation. The method includes recording a charge to the content provider for the presentation, the charge determined using the hierarchy and charge values associated with the multiple target criteria. The method can be implemented using a computer program product tangibly embodied in a computer-readable storage medium and comprising instructions that when executed by a processor perform the method.

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: 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: A computer-implemented method for controlling content distribution includes forwarding information associated with a user to a device operated by the user, the information being configured for use in selecting content from any of multiple content providers for a content distribution to the user. The method includes receiving, in response to the information, an edit of the information forwarded from the device. The edit identifies a first content provider and including a first modification of the content distribution regarding the first content provider. The method includes storing the edit in association with the information such that the first modification is taken into account in the content distribution. The method can be implemented using a computer program product tangibly embodied in a computer-readable storage medium.