• 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
• The W3C MarkUp Validation Service
  Verify that your web page conforms to W3C standards (free)
  W3C's easy-to-use markup validation service, based on SGML and XML parsers.
  html hypertext language markup service validation w3c
  in Development > Web development with css development html page standards verify w3c web by 105 users

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