• An Annotea Bookmark Schema
  Annotea [Annotea] is a W3C Semantic Web Advanced Development project that provides a framework for rich communication about Web pages through shared RDF metadata. This metadata can be stored locally or in one or more user selected RDF servers. The first application of the Annotea infrastructure was an RDF schema for Annotations; objects with multiple properties intended to convey comments between human readers of a Web document. The Annotea Annotation schema [AnnotationNS] defines properties for identifying the document being annotated, a specific context within that document to which the body of the annotation refers, the author of the annotation, and more. Annotea clients can provide a variety of presentations of these annotations. As the Annotea framewor
  in Development > XML with bookmark metadata rdf schema w3c xml
• Database schemas for tag-based systems
  You want to have a database schema where you can tag a bookmark (or a blog post or whatever) with as many tags as you want. Later then, you want to run queries to constrain the bookmarks to a union or intersection of tags. You also want to exclude (say: minus) some tags from the search result.
  in Development with database development schema tag by 2 users

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