Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for collaborating on projects. One of the methods includes receiving, at a user device, an indication of an update to a project, the project being identified by a project identifier. A camera device associated with the user device is activated in response to receiving the indication of the update to the project. Subject content is provided to a serving system, and the serving system provides a presentation thread of a project identified by the project identifier, the presentation thread comprising the subject content of the subject. The presentation thread of the project is presented on the user device.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for rating subjects. One of the methods includes receiving, from a user device, a subject content query requesting subject content corresponding to ratings of one or more real-world subjects. A location and a user selection of a radius are received. One or more subject content search results are obtained that satisfy the subject content query, including identifying one or more items of subject content that are each associated with geographic locations within a threshold distance to the location of the user, wherein the threshold distance is based on the radius. The one or more subject content search results are provided in response to the subject content query.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for rating subjects. One of the methods includes receiving, at a user device, a rating of a real-world subject. A camera device associated with the user device is activated in response to receiving the rating of the real-world subject. Subject content of the rated real-world subject is received. The rating of the real-world subject is associated with the received subject content.