Personally I think it depends on the scale. As soon as you have actions that can't easily be implemented in server side code or have a large divergence in possi

Personally I think it depends on the scale. As soon as you have actions that can't easily be implemented in server side code or have a large divergence in possible behaviour for clients, you can say "you need javascript to view this" (pretty much, when it can be called an application). I find the 'javascript to enhance' guideline helpful to. Then sites are more likely to be functional (but not pretty) in older browsers. A good example is javascript to make menus slide, but which use CSS to make them come up.