1. A collaboration system, comprising: a non-transitory computer readable storage medium, comprising: a collaboration model, comprising: model entities that provide access to information related to a collaborative activity, the model entities including a model entity contained in a first hierarchy of a first type and contained in a second hierarchy of a second type; the first hierarchy neither containing nor contained in the second hierarchy; and configurable permissioning controls established for each of the persons involved in the collaborative activity, and machine instructions for collaborative activity operations according to the collaboration model; and a processor that: accesses the collaboration model and the permissioning controls, and executes the machine instructions to: enable display of a graphical user interface; determine a type of access by a person to the model entities by: reading the permissioning controls, and comparing the permissioning controls to an identification of the person entered by the person in the graphical user interface; and perform the collaborative activity operations on the model entities to: grant access by the person to the model entities according to the determined type of access, view, create, modify, and delete the model entities, make changes to the model entities immediately available to all persons authorized to access the model entities, assign the model entities to locations in the first hierarchy and the second hierarchy, access and modify the information related to the collaborative activity, and display the model entities in the graphical user interface according to the locations in the first hierarchy and the second hierarchy.