Wikipedia

It is common in online conversation among some Internet users to use a fictitious closing tag patterned after HTML: . Over time, it has evolved to lose the angle brackets (/sarcasm) and has subsequently been shortened to /sarc or /s (not to be confused with the valid HTML end tag used to end a struck-through passage).[20] Users of the website Reddit frequently denote sarcasm through the use of /s, as shorthand.[21] This usage later evolved into tone indicators.

Wow, I didn't know the /s had an origin story. Pretty cool.

I mean I can barely remember and hate using /s. at least it annoys me that things which to me is obviously sarcasm, cannot be seen as such on the internet. granted when hanging out and being sarcastic it was sometimes a win to get the double take or eh response.

I like this one ⸮, I'll try to use it, it's more elegant than /s.

That backwards questionmark doesn't work. I'm only seeing a square. But now that I've copied your text I'm seeing it in the quote. Weird.

The irony of having to explain your sarcasm punctuation after using sarcasm and punctuating it in way nobody understands.

Ah the interrobang, an elegant weapon for a more civilized age

I never knew ~.