Extended (or rather, distended) Markdown flavors always make me queasy, and I don't love the snippet from Code Hike. In my mind, Markdown is fundamentally intended to be lightweight--something for a Reddit post or a blog comment. Heavily extending its syntax instead of choosing a saner syntactic basis strikes me as ill-advised. But one can't deny the advantages for adoption to be had from using Markdown as a starting point, and the project appears to be very popular, so perhaps worse is better.