We recently added a button on the Open WorldCat rendezvous page to find other 'editions' of the found item. This is an interim approach to implementing the FRBR model which clusters versions of a work. It helps find, for example, translations of a particular item.
See Reading in the dark and click on 'other editions of item'. (Click through from a search engine to see the subject headings and author fields hot linked. Here is the Google result - click through.)
This is an example of turning a service inside out. What we are doing is exposing on the open web functionality that was previously only available within a catalog or retrieval system. Over time we will enhance the functionality available at this page. It is one way of releasing the value of the accumulated library investment in structured data.