[ThinBold]

I mean we do have a lot of (perhaps too many) markdown dialects today. Wikipedia, wordpress, github, stackexchange, you name it. Last time I was using a Q&A forum for calculus course, it uses $$ to start and close a MathJax div.

[smcl]

My fave is Jira, where they have one syntax when creating an issue and another for editing it

[fhars]

Well, at least that is the obvious way to delimit a math div, isn't it?