Open for business: WordP.ad, for all your markdown-writing needs. I use it all the time. What fun stuff are on the site, besides your boring old markdown writing platform? Well...

• Dialogue Punctuation Formatter
  You don't think about quote mechanics until you've typed a hundred lines of conversation and realize half your commas sit outside the quotation marks. One click pulls every trailing period and comma inside the quote ("Like this,") automatically.

.... Et cetera.

Impressive, right? (Say yes.)