Dropbox , Mega.co.nz , Copy.com ... edit : sorry I mis-read your question. I think you're asking for drive space with ability to edit docs on the drive itself

Dropbox , Mega.co.nz , Copy.com ... edit : sorry I mis-read your question. I think you're asking for drive space with ability to edit docs on the drive itself right ? one-drive does that, but if you're concerned about security maybe you get a server and install microsoft office webapp server 2013.