Thanks for the question - we've focused initially on creating a low-barrier-to-entry front-end for LaTeX, but which still worked in the native language. Which way we go in future will depend on the feedback we get on writelatex!
This would be really easy to implement using pandoc (http://johnmacfarlane.net/pandoc/), which converts Markdown with extensions and LaTeX formulas into LaTeX. I think it supports Org-mode too.
Markdown would be excellent for sharing short notes and ideas among mathematicians, as opposed to full-blown papers.
Also, great job! I like how simple and efficient the interface is.
Thanks for the question - we've focused initially on creating a low-barrier-to-entry front-end for LaTeX, but which still worked in the native language. Which way we go in future will depend on the feedback we get on writelatex!