Tim Bray calls for editors that do for XHTML what Word did for other documents.
Building an XHTML editor in the browser is painful –less painful since contenteditable arrived.
Managing content through the server, however, isn’t horrible. You can point something as basic as Blosxom at a directory of markup and publish it. Using WebDAV, your operating system provides the interface for organizing the site.
But editing the stuff remains a client-side task.
Update:
Tim points to Johathon Delacour’s misadventures with in browser editors.
My current process for editing this blog is to write in BBEdit, then use Markdown and html2text to move back and forth.