Museums are rapidly digitizing their collections, and face a huge challenge to annotate every digitized artifact in store. Therefore they are opening up their archives for receiving annotations from experts world-wide. This paper presents an architecture for choosing the most eligible set of annotators for a given artifact, based on semantic relatedness measures between the subject matter of the artifact and topics of expertise of the annotators. We also employ mechanisms for evaluating the quality of provided annotations, and constantly manage and update the trust, reputation and expertise information of registered annotators.