And by original, I include the concept of using traditional ASCII markups. For instance, doing this (asterisks) for emphasis long preceded Markdown. As did _this_. As did -this- and various other ASCII markings. None of those are innovations of markdown, or are they inventions of John Gruber, and their intention is directly paralleled in HTML.
Beyond that...the link mechanism of Markdown is and always has been pretty weak, and outside of that it's pretty marginal grounds.