Is Markdown only used by nerds?

I'd say so, although I'd use the term advanced user / power user instead of nerd, as I feel the interpretation is less contextual.

My personal observations on why that could be the case: - Markdown has a very technical origin - I really only saw it gain adoption with GitHub (please excuse if that was only my perception and it gained the popularity elsewhere). So far, it hasn't spread too far into the non-technical world. - The average end-user prefers a WYSIWYG style. Yes, some markdown editors are rich editors with WYSIWYG controls, but then you could argue the user is not really writing markdown. - The way markdown is defined, it works really well with mono-spaced fonts. Again, great for technical content (e.g. code), not so great for lengthy paragraphs. - I am always surprised with how many people are using the visual WYSIWYG buttons to make a word appear in bold vs. how many use CMD/CTRL + B, in spite of writing quite a lot. Common users may not spend the time to learn the code?

The problem that I always have with Markdown is that there is no real standard for it. Every system seems to have its own version.

Non-nerds just rarely know about it (I see no reason to avoid using it otherwise). I've advised a non-tech gurl to use Typora instead of Word for her study notes and she's been using it ever since very happily. Sadly you can't even download Typora without the browser warning that's weird ("unusual for people to download") and you probably shouldn't. I use and recommend Typora (of all the other Markdown-aware editors) because besides having all the handy features it also is visually beautiful - this is a good inspiration and concentration buff.

   yes.

I don't see it being widely overtaking Google Docs or Microsoft Word anytime soon. This is why it will always be used by 'nerds'. [0]

[0] https://hackernoon.com/say-yes-to-markdown-no-to-ms-word-be4...

I am no nerd by any stretch, but .md allows me to have an optimal solution for self hosted note taking system (Obsidian)

Given that Reddit, Stackexchange, and Slack now have a rich editor by default, instead of markdown, I’d say yes.

It depends on the nerd I guess. A lot of nerds I know are die hard Plain Text fans. I've used it on a wiki or two, but have little use for it otherwise.