I don't totally agree with you, as you are going to see online backups as a second or third backup, we all know, we should have backups on 2-3 different medias/places and here solutions like Carbonite or one of the other backup services in the cloud are doing a great job. The big Advantages are that you can 'restore' your files from anywhere. And by the way youre putting Dropbox in there as an online backup solution; its more a way of keeping files in sync between two or more computers.