Essentially a way to import a block of dependancies (scripts and styles) into an HTML document.
<link rel="import" href="imports.html">
It doesn't actually just plop the content from the referenced file where you call it though, like an
@import does in CSS or and include does in a server side language. HTML could very much use that.
The following is a guest post by Rob Dodson (@rob_dodson). Rob and I were going back and forth in CodePen support getting Polymer (a web components polyfill, kinda) working on a demo of his. We did get it working, and things kind of evolved into this article. Take it away Rob.
Update: Rob updated this article on March 5, 2014, getting everything up to date, as this is a rather fast-moving technology at the moment.
Update: Updating again September 9, 2014!