Shadow DOM background reading

Let's all try to get some reading done before next week's call, so we can have a good discussion on the relevant complexities.

Here's an introductory article that is, I have been told, up to date with the latest spec:

http://www.html5rocks.com/en/tutorials/webcomponents/shadowdom/

Here's the actual spec:

http://w3c.github.io/webcomponents/spec/shadow/

I'm going to make an attempt to at least skim, and perhaps deep-dive, into the spec text.

I'll let Alex take it from here, giving us pointers on recent controversy threads. Happy reading!