Online Backup (aka “Cloud Backup”) is similar to Cloud Storage, but with some notable differences. While an Online Backup service will automatically transfer files to the cloud for safe keeping, a Cloud Storage service relies on the user to initiate the file transfer.
Online Backup is typically a set-it-and-forget-it type of thing, where everything hums along in the background after the initial configuration. Cloud Storage can be thought of as your own hard-drive in the cloud, where it is accessible from any networked computer anywhere.
Both Online Backup and Cloud Storage services typically offer a mechanism to share files with others.