[sprin]

Etherpad (http://etherpad.org) is an OSS cloud document editor app. It has a pretty reasonable set of formatting, revision, and import/export options out of the box, and also a large set of plugins (http://static.etherpad.org/plugins.html). Supported import formats are plain, doc, docx, odt, rtf, and html.

There's a demo on the homepage that runs on Sandstorm.io, so you can very easily self-host or use managed hosting via the Sandstorm framework (https://sandstorm.io).

EtherCalc (https://ethercalc.net/, not related to Etherpad) is an OSS cloud spreadsheet app. Demo on homepage, also available on Sandstorm.

Sandstorm has several other office/productivity apps, and in my opinion, is the clearest route to an effective OSS cloud office suite. I am hopeful for LO Online, but tile-based rendering seems like a bad choice. I have no doubt it will be packaged for Sandstorm at some point, but Etherpad is looking much better as of now.