It's an escape character.

/s all the way. If its fucking shit up thats the devs fault.

I always assumed it was shorthand for an html close tag like

</s>

Until markdown gets a sarcasm thing at least.

-s is better.

I use arch, btw

<sarcasm>

</sarcasm>

Always slash forwards. Never slash backwards.

Wait, in the first one it looks like the S has a cape.