There's been a lot of action lately in new web-based content management systems, but imho, all the systems other than the worldoutline software I'm working on, are barking up an wrong, old tree. I had to go on a road trip to figure that out.
Key idea -- there is the equivalent of source code in content. Behind the rendering of pages, of which there can be many kinds, there are words and structure. The words are like the furniture and equipment in an office building. And the structure are the beams, elevators, water pipes, electric lines, network infrastructure.
Most content systems have very simple and fixed structures. Authors and designers can't do anything with the structure. In a way this is good because they don't have to do anything. But eventually this becomes too limiting. It's a limit I haven't had to deal with for a very long time, so sometimes I forget that almost everyone else is living with that limit.
Anyone who has lived in an outliner totally understands the idea of user-editable structure.