Let's say your computer gets a virus, and it deletes everything on your hard disk. This will also delete all your Dropbox files. Luckily Dropbox keeps versions

Let's say your computer gets a virus, and it deletes everything on your hard disk. This will also delete all your Dropbox files. Luckily Dropbox keeps versions. Now imagine the virus purges deleted files. Now you have to contact Dropbox support. The type of backup you want depends what you are trying to protect against. Maybe you'll decide you want want a physically separated medium that is rarely connected to your PC.