The solution of online backup relies on two complementary technologies: the backup software and the outsourced servers.
The restoration of your files is an easy operation:
E.g. A SME suffered a loss (flood, fire…) and the server is out of use. The only backup that had that company was in the same local and suffered the same distasters than the server. By suscribing to this service of online backup, it could have installed its data on a new server and prevent the total loss of its data.
Think about it, data loss occurs so quicly...