Storing and retrieving multimedia web notes

Digital annotation of multi-media documents adds personal information to them. Sharing of annotations among different users allows discussions and cooperative work. We discuss architectural solutions and storage schemas to the problem of annotating multimedia documents with multimedia objects. Annotations can refer to whole documents or single portions, but also to groups of objects in the same document. We present a new digital annotation system with a client-server architecture, where the client is a plug-in for a standard web browser and servers are annotation repositories. Annotations can be retrieved and filtered, based on their metadata descriptors, and possibly on their content.