Perhaps an embarrassing case in point I have been a developer, sysadmin, infra architect, and generally in IT industry for couple of decades. I am not professional but dabble in HTML/CSS/JS. Certainly use social media.

And every now and then think to myself "I should check what this 'markdown' thing is" :P

Checking it now, I can absolutely agree that 100% of my non-developer friends will believe it is code and beyond them [both untrue as facts but true as perceptions]. And trying to persuade them otherwise will only convince them further how much out of touch with "the real world" I am :D

I don't mean they've heard of it, indeed what most of these platforms support isn't Markdown but a similar simplified ruleset. I mean that more people than one might think are using the general concepts of Markdown on a daily basis.