Nothing
Here is a test to see abilities when dealing with equations such as $y=X\beta$ handles
Or single line
$$y=X\beta$$
And a more complex formula
$$\frac{a}{(\sum_{n}^{i=1}{x_i+1})+k}$$
Results:
2014-07-17
Copy-paste OK for the simple formulas but nothing else
Complete failure for opening directly in LibreOffice/Word
With word_document - works perfectly
Any scripts or data that you put into this service are public.
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.