> Great find. But, I have seen Google doing similar thing using HTML5 entirely.

"HTML5 entirely" doesn't really mean much, for example my website uses mostly HTML 4.01, but is HTML5 as well (since it's mostly backwards compatible).

eg. If you're using <div> tags then you're using HTML5.

This is more for doing layout techniques so it's more of a library where HTML5 is a markup language. You should think of this more like jQuery.