That, and also needs beyond the initial creation: Adding new types of content, modifying things without having to start from scratch, being easy to diff for change reviews and for merge-conflict resolution, supporting search engine crawlers, deep links, permanent links, interacting well with the back button. And that's without getting into the cases in which you have content that updates in real time, user content, the need to support offline mode, or any of the things that blur the website / application line.