MediaFire Desktop for Mac
is a service that allows you to keep a backup of documents stored on your Mac in the cloud. The tool works by placing a folder and shortcut on your desktop and taskbar. As your computer is working, any documents placed in the folder will automatically be backed up up on the cloud server. It's easy to use, will protect you from data loss, and a free version is available with 10 GB of storage. You can upgrade for more space for a fee.