markdown tried very hard to encode conventions that were already used in Usenet, email, and other text media

For those of you who weren't there:

  *bold*

  _underline_

  ~strikethrough~

  /italics/

  > Quotation

  - list
  - list
  - list

Your quotation and list syntax should work out of the box in most Markdown flavors (HN has a very non-standard and crippled version - basically nothing other than italics, paragraphs, and code/preformatting works.)

Strikethrough and bold are doubled to avoid common ambiguities. Your underline should technically work, but it comes out as an <em> (emphasis) tag, which is rendered as italics in most browsers.

But Usenet style didn't have a trendy name, an 'inventor' or Github stars. So it didn't exist.