It is possible to link your Digital ocean server to a DropBox account in order to synchronise files between DropBox and the server. In this way yo can use mobile phones to publish files to DropBox and these will be automatically synced to your server.
Dropbox has a headless Linux client. It's entirely self-contained. You can use a standard Ubuntu image without any package dependencies. You can even make a temporary user to install and test it without using root. You can use such a Dropbox setup to sync all or part of a Dropbox account on a Droplet. I wouldn't use it for production, but this is promising as a quick and easy prototyping and development tool. It's also handy if you want to link up temporarily and get rid of some clutter if you have a big image sharing folder or the like. You can then view and organize using your standard Desktop tools, and unlink afterward. It also means you can use any of a myriad of iOS and Android programmers' text editors with Dropbox integration built in. These let you update the site in real time. If your connection drops, you don't get booted as with a shell. Instead, it will merely sync when you reenter a coverage area.