Online storage is not backup

I recently had a user with a corrupt Microsoft Word file.  He felt he had a backup since he was using Microsoft OneDrive.   
Unfortunately, services such as OneDrive, Dropbox, and Google Drive will not protect you again accidentally deleted files, modified files, or corrupted files.   These services are designed to synchronize files between different systems and the cloud.  If a file is deleted on one computer or becomes modified or corrupted on one computer, this will propagate to the cloud and all the other computers.   
In order to protect against this, you need to have a backup service which provides file history.   Crashplan and Carbonite provide this type of backup.  They will retain snapshots of the files at various points in time.   
Since I had implemented a proper backup at this user's site, I was able to restore a copy of the file from before the file became corrupted, much to the user's delight.