If I enter the following mark-down source:
into a question or answer, then it works, but in a comment it doesn’t. The asterisks remain literal and don’t turn into italics.
There are too many edge case (in particular around URLs) to allow the full set from proper Markdown here; the two will never be identical in all regards.
However I'm willing to add characters to the "can begin or end formatting" whitelists that shouldn't cause any problems and that are valid use cases for appearing next to formatting.
For the next build, I have added the majority of typographics quotation marks to the list: single and double guillemets, single and double quotations marks (bottom, top 9-shaped, and top 6-shaped). The ellipsis is now allowed at the end of a formatted piece of text as well.
comment mini-markdown is much, much stricter, and the characters adjacent to the italics or bold must be on the whitelist.
Unicode character U+201d