I came across this yesterday at cosource.com, and I think it's worth checking out. It's an all-XML, open source web-app platform. http://www.risource.org Excerpts from the faq: In the PIA framework, each application consists of two parts: 1.A collection of task-specific XML pages which contain active-processing tags (<if>, <include>, <repeat>,, etc); These look very much like HTML pages. 2.A core software layer (including a dynamic XML processor) that is shared by all applications Broadly speaking, the PIA does three kinds of things: Act as a web server, reading and processing active-XML documents and serving up HTML for view. Act as a browser proxy, intercepting incoming HTML pages and modifying them (e.g. deleting ads or filling-in forms) and showing you the modified page. Act as a document processor, processing active-XML documents into HTML or XML files. In each case, the PIA processes a markup document to produce another markup document, based on the particular active tags ("tagset") associated with the source document.