Abstract: Methods, systems, and apparatus for identifying and using unambiguous terms are described. In one implementation, a method for identifying unambiguous terms includes accessing textual content that is included in one or more electronic documents, and extracting one or more terms from the textual content by identifying single words or groups of words in the textual content that relate to a common concept. The method includes analyzing the extracted terms, using a computing system, to determine whether the extracted terms are ambiguous, where a term is determined to be ambiguous when the term has different meanings depending on a context in which the term is used. The method also includes identifying a set of one or more unambiguous terms from the extracted terms. In some implementations, the method may also include using the set of identified unambiguous terms to identify supplemental content to deliver to a user of a computing device.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer-readable storage medium, are described for providing content to a user. A method comprises: receiving an update for publication to an activity stream associated with the user, the activity stream being produced by a social application executing on one or more server computers and being published for consumption by one or more subscribers to the social application that have been designated by the user as being authorized to receive the update; and distributing additional content to the user based on the received user update.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer-readable storage medium, are described for providing content to a user. A method comprises: receiving an update for publication to an activity stream associated with the user, the activity stream being produced by a social application executing on one or more server computers and being published for consumption by one or more subscribers to the social application that have been designated by the user as being authorized to receive the update; and targeting additional content to the user based on the received user update.