From @notriddle’s link:
GitHub-flavored Markdown is supported by kramdown by default, so you can use Markdown with GitHub Pages the same way you use Markdown on GitHub.
In other words you can use CommonMark with GitHub Pages the same way you use it on GitHub.
And yes, even kramdown supports CommonMark. Does that mean we get to add kramdown’s numbers to CommonMark’s?
That’s a rhetorical question, so please don’t answer. This debate is starting to get silly, and sounding like national politics. Let’s get back to progress with CommonMark, whether that’s nailing 1.0 first or declaring it done, we need to move on to 1.1 asap. We need to move to head off even more fragmentation.