That's not a real solution though, it's half of a solution at best. All you're providing is a place to dump files, with none of the services that a backup solution would actually provide.
This may be fantastic for technical users, but it would be a nightmare if I used this to manage the backups of friends and family.
Ultimately I switched to CrashPlan, as that not only gave me offsite backups (for far cheaper than you, sorry) but using the same technology also offers me on site backups and the ability to back up to any server I control and choose. This allows me to have my friends backup to the CrashPlan service, to their own local drive, and to a computer I setup just in case both of those fail. Best part is I'm not stuck doing a bunch of work.
As a final note, your service is extremely expensive compared to just about everything else.
This may be fantastic for technical users, but it would be a nightmare if I used this to manage the backups of friends and family.
Ultimately I switched to CrashPlan, as that not only gave me offsite backups (for far cheaper than you, sorry) but using the same technology also offers me on site backups and the ability to back up to any server I control and choose. This allows me to have my friends backup to the CrashPlan service, to their own local drive, and to a computer I setup just in case both of those fail. Best part is I'm not stuck doing a bunch of work.
As a final note, your service is extremely expensive compared to just about everything else.