For  quite  some time, I've written all my notes as simple text files.
  Or groff.

  Text files are the most  basic  form  of  taking  notes.  The  obvious
  problem  is that you'll have trouble using them anywhere but your text
  editor.  There's no standard format. Only you know what a "h1" is.

  groff is sweet because it can produce  high  quality  PDFs.  And  it's
  rather simple. But virtually no "modern" application supports it.

  Enter Markdown.

  It's  simple. It's easy to read and easy to write. And, here comes the
  bonus, quite a lot of  modern  web  applications  support  it.  GitHub
  renders  Markdown documents, there's a Confluence plugin for Markdown,
  and so on.

  I think I'll start writing a lot more Markdown documents in  the  near
  future.