The Budapest Open Access Initiative clearly identifies, in its original definition of Open Access from 2001, that OA is not only about making research outputs freely available for download and reading. The aspect of reuse, which includes being able to index and pass OA content to software, is firmly embedded in the definition, opening new possibilities for the development of innovative OA services. However, while the growth of OA content has been used in the last decade as a benchmark of success of the OA movement, the successes in terms of finding and reusing OA content are much less documented. We believe that in order to fully exploit the reuse potential of OA, it is vital to improve the current OA technical infrastructure and facilitate the creation of novel (possibly unforeseen) services utilising the OA content. According to Figure 1 below, this OA content consists of OA papers, OA research data and all possibly inferred (or extracted) knowledge from these materials. The services that can access and manipulate this content can be tailored to different audiences and serve different purposes. [...] The Confederation of Open Access Repositories states: Each individual repository is of limited value for research: the real power of Open Access lies in the possibility of connecting and tying together repositories, which is why we need interoperability. In order to create a seamless layer of content through connected repositories from around the world, Open Access relies on interoperability, the ability for systems to communicate with each other and pass information back and forth in a usable format.