Recently there has been a tendency for the research community to move away from closed hypermedia syustems, towards open hypermedia link services which allow third parties to produce applications so that they are hypertext-enabled. This paper explores the frontiers of this trend by examining the minimum responsibility of an application to co-operate with the underlying link service, and, in the limiting case where the application has not been enabled in any way, it explores the properties and qualities of hypermedia systems that can be produced. A tool, the Universal Viewer, which allows the Microcosm Hypermedia System to co-operate with applications which have not been enabled in introduced and a case study is presented which demonstrates the functionality that may be achieved using entirely third party applications, most of which have not been enabled.