1. A method for operating an online service facility selectively accessed by multiple end-user computers, the online service facility including a plurality of online data centers operated by an online service provider (OSP) to store end-users' data objects relating to a variety of online services that the OSP renders to its end-users, the method comprising operations of: providing an aggregated catalog that contains information including: (1) metadata identifying end-users' data objects residing in the online data centers, and (2) metadata identifying end-users' data objects residing in respective end-user computers; detecting new storage in the online data centers of prescribed types of data objects owned by the end-users; communicating with the end-user computers to identify prescribed types of data objects newly stored in the end-user computers; updating the aggregated catalog to list the newly stored data objects from the online data centers and the newly stored data objects from end-user computers; and responsive to each request by an end-user, searching the aggregated catalog and utilizing results of the search to provide an output for display at the requesting end-user's computer, the output comprising a consolidated listing of data objects of the end-user residing in the online data centers and data objects of the end-user residing in the end user's computer.