User 1 is hosted by VW A and user 2 is hosted by VW B. User 1 has user 2 on his friends list. User 1 decides to transfer an object in his inventory to user 2. User 2 is offered the option to accept the object transfer or decline. User 2 accepts the transfer and the object is now in user 2’s inventory.
Content reuse is a related use case with slightly different requirements. For example, an organization that creates models for objects & scenes would like to realize those digital assets in multiple virtual worlds (build once, use many). The requirements are a bit different because solutions that involve offline transformations would be acceptable for content re-use. Offline solutions would probably not work for end-user transfer of objects between virtual worlds.