I want to create a small app that will work on the background and automatically create a backup copy of all the new and modified files. Also, user can drag & drop files into the application to store files. User will be able to access his backup copy and restore/open files from any computer connected to the internet (just like a virtual driver). Application will use my Amazon s3 (or like) account to store all the data - each user will get a folder (bucket) to store all his files. Application should be very light and fast (don't slows down the computer). I will offer this service to my clients; thus, admin should be able to control the users accounts (delete users, manage buckets etc.).