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.