Link to CommonMark

[mcandre]

The CommonMark project provides a specification to help multiple implementations resolve conflicts.

http://commonmark.org/

[waylan]

IMO CommonMark is not Markdown. In fact the specification is in direct conflict with the Markdown syntax rules on a few points. So, no it is of no use to Markdown inplementors AFAICT.

[mcandre]

It's still a form of Markdown, even if we don't treat it as the canonical form it wants to be. It's worth listing alongside the other implementations.

[davidchambers]

I agree we should list it, perhaps with a note about its divergence from "proper" Markdown. Every implementation is divergent to some extent. Fancy submitting a pull request, @mcandre?