MathJax just added ASCIIMath support, and I think it'd be great to support it as an option, alongside regular \$\LaTeX\$-based MathJax.
In many posts (such as this one) people forget to or are too lazy to properly format units:
What we see:
\$5 kg\$(\$5 kg\$)
What we should see (pretty!):
In ASCIIMath, you can use quotation marks ("") to delimit roman text, so the properly formatted variant becomes