1. A system for sharing data objects among applications, comprising: a client library coupled to a requesting application and operable to request data objects of a data-object set; a set of code (SOC) in communication with the client library and configured to parse any request from the client library and retrieve any data objects of the data-object set; a registration module configured to register subscriptions from or on behalf of the requesting application, wherein each subscription has a filter criteria; and an event notification module configured to receive an event message from the applications, compare the at least one data object in the event message with one or more of the subscriptions, and selectively notify the subscribed applications, including at least the requesting application, in response to the comparison on the basis of any matches of the filter criteria, wherein the selective notification includes a return of any matching data objects to the client library coupled to at least the requesting application; and wherein the event notification module is operable to identify at least whether the event message indication is an out-of-scope or an into-scope event.