You originally asked about a program that you use (or would use?) written in Haskell. Someone brought up Pandoc, the swiss army knife of Markdown and similar formats, and every programmer uses Markdown in some capacity. Then you chose to fixate on the phrase “mass market” software, as if that was relevant to your original claim: a program that a programmer would use.
Which demonstrates my point. Someone with this attitude has already dug their heels in and made up their mind.
https://news.ycombinator.com/item?id=40695628
https://hn.algolia.com/?q=markdown