Progressive Reduction

This is really interesting, but I'd like to see some level 1/level 3 comparisons for the app as a whole. What is being gained by the user progressing? A more minimal, less cluttered interface? You would think the beginner is the one that needs that interface, not the expert. In addition, how do you bridge the gap from "icon on a button" to "using keyboard shortcuts", which is where your expert users are really going to be spending their time.

That being said, I think the adaptive interface concept is really intriguing, and if executed right could be really useful

I guess the Hacker News mods really don't like LayerVault these days. This was removed from the frontpage.

This is a great technique, but I am concerned that instead of augmenting good, flexible responsive design, it will replace it. It has the negative side effect of creating a lot of ambiguity (what does the checkbox mean without the label, discovery is a lot harder now).

Just be careful with it, I suppose. It is not the solution to all your resolution troubles. :-)