Abstract. JeromeDL is a Semantic Digital Library engine. It uses Semantic Web and Social Networking technologies to improve browsing and searching for resources. With JeromeDL’s social and semantic services every library user can bookmark interesting books, articles, or other materials in semantically annotated directories. Users can allow others to see their bookmarks and annotations and share their knowledge within a social network. JeromeDL can also treat a single library resource as a blog post. Users can comment the content of the resource and reply to others’ comments and this way create new knowledge. All data stored in the library is available in RDF format for querying and processing by other applications. Also the result of every search or browse action is immediately available as a link to RDF. Innovative MBB (MultiBeeBrowse) component offers multifaceted navigation and provides SOA for integration with other applications. TagsTreeMaps allows to easily filter out resou...