Really neat. I must be living under a rock, but I never had heard of this before. It seems to bring a lot of the advantages of component-oriented development with it - just declare and go and the implementers will have taken care of the necessary wiring behind the scenes to make the components work. What I don't have a feel for though is what disadvantages it might bring from component oriented development - how easy for example would it be to change the style and/or behavior of the expanded component dom objects, in a way that the original developers never thought of, if need be? In any case, very cool and thanks for posting.
To change the style and behavior, you just use the DOM as you normally would. You can access the inner DOM elements of a component with regular ol' JS and style them normally with CSS if exposed - but even if they were created as Shadow DOM elements (in browsers that support Shadow DOM), you can still style them with CSS ;)
