1. A method comprising: receiving, by a mobile device, a managed application from an application server during a first communication, the managed application being constructed to operate in accordance with a set of one or more policy files defined independently of the managed application; receiving, by the mobile device, the set of one or more policy files from the application server during a second communication different from the first communication, the set of one or more policy files being stored on the mobile device separately from the managed application; and running the managed application on the mobile device in accordance with policies defined in the set of one or more policy files that is stored on the mobile device separately from the managed application, wherein the policies defined in the set of one or more policy files, when applied to the managed application, cause the managed application to restrict a data-sharing feature otherwise made available on the mobile device.