I’ve been looking for some time trying to find a nice and easy file management server I could host that would give me the same abilities as a ‘Drop Box’ or ‘Google Drive’.  Finally stumbled on an open source server that does just that, it’s called Pydio and installs on a standard LAMP server and gives you that capability.  So far I’m really impressed, it has the drag and drop features that you’ve come to expect and does a heck of a job.