I can’t understand why I’ve never run across this website before. It is outstanding in my opinion. I’ve read many Markdown syntax and advocacy pages before but don’t recall ever seeing this one. I especially like the Best Practices sections.
Let me know if everyone else is familiar with this particular website and I’m just late to the game. 
I’ve never seen it. Quite handy! Thanks for pointing it out!
I really appreciate the Guide’s mixing of raw HTML and markdown. Such a healthier approach than engaging in the syntax wars / focusing on Markdown’s constraints!
Yeah-but as the guide points out and I’m sure you know, “Markdown applications don’t agree on how to handle blah-blah” and “You can use blah-blah in nearly every Markdown application, but it’s controversial.”
Markdown has never been a real file format like Microsoft’s .doc, .docx, .rtf ( or even NeXTSTEP’s .rtfd). Markdown is just a handy and sometimes frustrating markup syntax with lots of variations and extensions for otherwise plain text.
As far as Markdown usage goes in real life, I’m sad that my favorite note-taker, NotePlan, does not support HTML but happy that my favorite document editor, Byword, does.