UI is indeed interesting. I've spent many years working on a solution to a similar problem (data, rather than files, although nodes in my app can contain attach

UI is indeed interesting. I've spent many years working on a solution to a similar problem (data, rather than files, although nodes in my app can contain attachments) and the UI is the part I've struggled with most. My most recent version isn't online (yet), but the basic design hasn't changed in the two years since I put this up: http://www.wittenburg.co.uk/Interact/ http://www.wittenburg.co.uk/Interact/ It requires a central server, but has a redundancy mechanism built in, in that if server A is unavailable the client simply goes to server B. It also has a panic password the hides/deletes data with a particular protective marking. Everything is encrypyed, and the server cannot identify any user, even given a user name. The app can easily be converted to work with files. The thing standing in the way of that is time. I have a four-month-old son that expects board and lodging.