Standard reminder that Markdown, while having no formal standard, tends to be implemented in broadly compatible ways across various systems. Yes, there are edge cases -- yes, I've seen the lists comparing different renderers; yes, I've run into differences once in a while myself -- but
in general, it turns out that the Markdown documents I wrote 15 years ago are still perfectly readable today, no matter what Markdown engine I drop them into. Or, you know, even if I
don't drop them into a Markdown engine, because the entire point of Markdown is to be easily human-readable, without "looking like code," before rendering in the first place.
Markdown isn't the be-all and end-all of markup formats, and there are valid reasons for using formats with strict specifications (e.g., AsciiDoc or ReStructuredText for certain kinds of technical writing). But the chances of Markdown documents suddenly being woefully unreadable in 20 years are roughly in line with the chances of plain text Unicode documents being unreadable in 20 years.