I just tested a use case of:

* paste in a Jekyll formatted markdown document * select all (which it couldn't do with something of 3,103 words - I had to do it manually) * shift+command+c to copy it as markdown * paste it into a TextMate window * The initial ---- markup to denote the header block is missing * The tags: [] array statement is converted into a header

I hope the author notices; it really is pretty.