PUNCT nodes in interlinear glossing.
I write in Markdown because it’s much easier to keep the flow of writing going without taking my hands off the keyboard.
I also like to write content in Anki cards in Markdown. Over the years there have been various ways in of supporting this through add-ons:
The venerable Power Format Pack was great but no longer supports Anki 2.1, so it became useless. Auto Markdown worked for a while but as of Anki version 2.
[N.B. 2016-03-26 Nathan Ifill pointed out that it is possible to use Anki’s built-in conditional replacement feature to do what I’m illustrating. I’ll have to work on another example!]
Anki is a widely-used flashcard application. If you’re learning a foreign language and you’re not using Anki, you should be.