1. A method of interacting with a shared data model, including: storing a plurality of applications in an application repository, each application executable in a runtime environment of a hosted application server and having an application owner identifier, the plurality of applications including a first application having a first application owner identifier, and a second application having a second application owner identifier that is different than the first application owner identifier; storing, in the shared data model, a plurality of content objects and a plurality of attributes, wherein the plurality of attributes includes: a plurality of application attributes, each application attribute specifying an application owner identifier of an application owning a content object with which the attribute is associated, the application being one of the plurality of applications stored in the application repository, a plurality of type attributes, each type attribute specifying a content type of a content object with which the attribute is associated, each content type specifying a plurality of attributes of its associated content object; and a plurality of privacy attributes, each privacy attribute associated with a content object and specifying a degree of access to the associated content object by applications other than the application specified by the application attribute of the associated object; executing the first application in the runtime environment of the hosted application server; executing the second application in the runtime environment of the hosted application server; receiving, by a system core from the first application, a request for a content object; determining by the system core, based at least in part on the application owner identifier of the content object and on the privacy attribute of the content object, that the first application has access to the content object; providing the content object from the shared data model by the system core to the first application responsive to the system core determining that the first application has access to the content object; receiving, by the system core from the second application, a request for the content object, the requested content object being the same content object as provided to the first application; determining by the system core, based at least in part on the application owner identifier of the content object and on the privacy attribute of the content object, that the second application has access to the content object; and providing the content object from the shared data model by the system core to the second application responsive to determining that the second application has access to the content object.