Amaya is a Web editor, developed jointly with W3C, to very simply edit and publish pages that include text (in HTML or XHTML), graphics (in SVG) and mathematical expressions (in MathML). Style is specified with CSS style sheets. Browsing features are seamlessly integrated with the editing and remote access features in a uniform environment. This follows the original vision of the Web as a space for collaboration and not just a one-way publishing medium. Amaya started as an HTML + CSS style sheets editor. Since that time it was extended to support XML and an increasing number of XML applications such as the XHTML family, MathML, and SVG. It allows all those vocabularies to be edited simultaneously in compound documents. Amaya includes a collaborative annotation application based on Resource Description Framework (RDF), XLink, and XPointer.