The help sidebar ("How to format") links to http://www.math.harvard.edu/texman/
That's a bit too extensive for us. (And it's for LaTeX proper, not mathjax so it has tons of irrelevant stuff)
Can we please write our own tutorial? (Or link to this proposed faq section?)
One of my friends told me she was intimidated by it and would read it when she had enough time--whereas TeX doesn't take that much time to learn the basics.
I am open to writing the tutorial myself.