WWWBackup is specifically designed for online backup. You can create real-time or scheduled backup tasks to protect your important data. The software automatically backs up your data to our secure and reliable storage. It can even backup file history so you can recover an older version. You can be sure that your data is very safe even if some major disaster happens to you, such as fire, flood, hurricane and theft, etc.
FileManager is a much more general software application, very similar to Windows Explorer (My Computer). You can upload/download, delete, copy, paste, edit, share, publish your files with drag & drop. Feature-wise, it covers online storage, sharing, publishing, synchronization and backup.
So feature-wise, FileManager also supports backup, but usually you need to manually drag & drop files from local to DriveHQ storage. You can use the Folder Synchronization feature to backup your files automatically, but it will keep only the latest version.
In short, WWWBackup is an application that you can setup your backup tasks and leave it running and forget about it. (i.e. set & forget); FileManager is an application that you can use it everyday for uploading/downloading/sharing/editing, etc.
Hope this is clear.