[mst]

The one issue with this is for things like markdown where a code block is space-indented - if you want an empty line as part of the code block rather than two code blocks then you need a line that contains -only- the indentation.

I would expect that emacs being emacs it's trivial to configure such lines to be left alone when relevant, but it's worth remembering that the edge case exists.

[ceving]

I never use indent in markdown. I always use ~~~. This makes copy/paste much easier.

[pmontra]

I use

  ```
  code
  ```

of course as first characters of lines. It appears indented here on HN.

I didn't know about the triple tilde.