1. A computer implemented method comprising: receiving at a server of a backend system that supports a network of users, an indication of a topic selected as a primary topic to be an anchor for a collaboration thread, wherein the backend system is to model the primary topic as a data structure available as a network resource to the users in the network, wherein the collaboration thread is associated with the data structure in the backend system; creating the collaboration thread in the backend system in response to receiving the indication, to provide a collaborative environment for multiple users; 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 of users unique to the collaboration thread, the audience defined by the primary topic and one or more additional topics selected as boundary topics that provide 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; presenting the collaboration thread to the assigned audience to enable only the assigned audience to participate in the collaboration thread; and dynamically altering the assigned audience after presenting the collaboration thread to the assigned audience by dynamically changing either the primary topic or a boundary topic of the collaboration thread.