Many users of Evernote backup their notes to external systems. Quentier should provide a way to do so as well. Currently notes can be exported to ENEX format one by one but for the needs of a backup this process would need to be more "bulk" and automatable. At least two levels are needed - backup all notes per account or all notes per particular notebook. This functionality should be possible to invoke from inside the app and from a separate command line tool.