Actually, I find myself in a position right now where they aren't on my computer. My MBP died, and I left my old job so my comp there was reformatted. I'm using a backup laptop that DB isn't installed on. So, were DB to get shuttered tomorrow, I'd lose everything.
I had briefly considered creating a service that would backup your Dropbox, GDrive, and SkyDrive but it seemed to me that because most of the users had the files on their computers locally anyway the idea didn't have a lot of value. That is why I ask.
I wonder if there is a service that will sync a local folder on my PC with more than one cloud service. For example, all my files in a folders are synced with Dropbox, GDrive AND SkyDrive.
Although yes, that's far from the average case.