Open Access (OA) is still a new concept. Last February 2012 was the 10th anniversary of the Budapest Open Access Initiative (BOAI), the first public declaration about OA and its infrastructure through the combination of two methods: Gold Open Access, allowing researchers to publish in OA journals, and Green Open Access, allowing researches to place their previously published works in OA repositories with the aim these will be open accessed and reused.
As consequence of the knowledge OA development, and also due to a most implication of the Governments and Institutions regarding OA policies, a very significant increase of OA resources has been achieved through journals and repositories. This rising of the free accessible knowledge and also of the virtual emplacements to store the open resources has caused an improvement of the tools, techniques and, specially, interoperability among repositories, all of them designed to offer solutions in a new complex and decentralized technological ecosystem. This way, the number of OA repositories has increased and they become in a key element of the eResearching infrastructure.