Although not specific to data science, if you write a lot of documents with mathematical notation, you are probably familiar with $latex \LaTeX$. $latex \LaTeX$ is a typesetting system common for mathematics.
There are now some nice resources to help you write and produce $latex \LaTeX$ documents collaboratively on the web.
- ShareLatex $latex \LaTeX$ writing and collaboration platform
- writeLaTeX online collaborative $latex \LaTeX$ editor
Another site, LaTeX Templates is just what you would guess. It contains of bunch of sample templates to make creating documents a bit quicker and easier.