W3C's Annotea Project, representing part of the W3C Semantic Web Activity, has been designed to "enhance the W3C collaboration environment with a system of shared annotations. 'Annotations' are external remarks attached to any Web document -- comments, notes, explanations, or other types of external remarks that can be attached to any Web document or a selected part of the document without actually needing to touch the document. When the user gets the document he can also load the annotations attached to it from a selected annotation server or several servers and see what his peer group thinks. The first client implementation of Annotea is W3C's Amaya browser and authoring tool. Annotea is 'open': it uses and helps to advance W3C standards when possible. For instance, the teams use an RDF based annotation schema for describing annotations as metadata and XPointer for locating the annotations in the annotated document." The public is invited to test the server/client tool; for testing purposes W3C offers a public annotation service.
For public testing and use: "You can use an interactive Web user interface for the annotest service. It lets you query the annotation database and see the RDF that is stored in there. You naturally need the annotest access database user id and password here too. It is also possible to install your own annotation server. We encourage others to install the server. Read the Annotea service installation instructions for further information. You can write other clients, plugins or proxies that communicate with the annotation servers. You only need to follow the Annotea protocols and understand the annotation schema..."
Annotea is a W3C LEAD (Live Early Adoption and Demonstration) project: "The W3C Consortium tries to use whatever web-based collaborative techniques are available, including distributed editing of documents in the web, and automatic change tracking. The Live early Adoption and Demonstration (LEAD) philosophy of W3C was introduced specifically for areas like this where many small pieces need to be put together to make it happen, but one will never know how large any remaining problems are until one tries..."