Annotea is a W3C LEAD project that has two main goals: 1) to support W3C collaboration by developing experimental tools that support shared Web annotations, and 2) to demonstrate RDF based metadata infrastructure and other W3C standards, such as XPointer.
Annotations are external comments, remarks, deletions, bookmarks etc. that can be attached remotely to any Web document or a selected part of it. Annotations offer users a document based view for the current issues, which is often useful when developing documents for Web standards as a group effort.
Annotea provides the first experimental implementation of RDF based Web Annotations. It consists of Amaya release that provides an interface for creating and presenting annotations and an RDF based metadata server for storing and fetching annotations. Both implementations are available at www.w3.org/?.
W3C also offers a public server for trying out annotations for demonstrational purposes. The goal is that users can try out how they could apply annotations in their own work and then install annotations servers for their own special purposes.