I've had really good experiences with ShareLaTeX<p><a href="https://www.sharelatex.com" rel="nofollow">https://www.sharelatex.com</a><p><a href="https://github.com/sharelatex/sharelatex" rel="nofollow">https://github.com/sharelatex/sharelatex</a>
Interesting development, to be sure. Here's my poorly considered qualm: a lot of what I prepare with LaTeX are for (hoped) publication of scientific results. Confidentiality is vital lest we get "beat to press". For instance, all editorial boards are sworn to such, (with varying degrees of success). So were I to use 'cloud' document prep, what assurances would I have of security in that regard? Perhaps it would be no worse than the average journal office, but were it proven, it would be seen as a feature.