The Open Archives Initiative (OAI) was an informal organization, in the circle around the colleagues Herbert Van de Sompel, Carl Lagoze, Michael L. Nelson and Simeon Warner, to develop and apply technical interoperability standards for archives to share catalogue information (metadata). The group got together in the late late 1990s and was active for around twenty years. OAI coordinated in particular three specification activities: OAI-PMH, OAI-ORE and ResourceSync. All along the group worked towards building a "low-barrier interoperability framework" for archives (institutional repositories) containing digital content (digital libraries) to allow people (service providers) harvest metadata (from data providers). Such sets of metadata are since then harvested to provide "value-added servic