1. A computer implemented method comprising: receiving at a server of a backend system that supports a network of users, an indication of a primary topic to be an anchor for a collaboration thread, the primary topic referencing a network resource to be modeled in the backend system; creating the collaboration thread in the backend system; associating, in the backend system, the created collaboration thread to the primary topic to anchor the collaboration thread to the primary topic in the backend system, including referencing the collaboration thread in the backend system as a context resource of the network resource of the primary topic; assigning an audience unique to the collaboration thread, the audience defined by the primary topic and one or more additional, boundary topics selected as boundaries to the primary topic, wherein the backend system includes definitions of associations of users to the topics, and the audience is assigned by intersecting users associated to the primary topic with users associated with the one or more boundary topics; and presenting the collaboration thread to the assigned audience to enable only the assigned audience to participate in the collaboration thread.