I've seen the storage provider close happen often, even seen the cloud storage provider loose data and say "oops, we don't have a backup, our TOS says we provide storage not foolproof backups".

Bank branches can close and safe deposit boxes get destroyed as well (hurricane Katrina).

You need multiple backups in multiple places. My most important data is always synced to 4 devices (phone, tablet, laptop and "server") not counting backups. So even if my home were destroyed, and backup locations destroyed my phone is still in my pocket with its copy.

And another scenario I hadn't encountered before. The dynamic dns provider I use to sync my mobile devices from outside my home network was attacked by Microsoft. http://www.noip.com/blog/2014/06/30/ips-...mpaign=takedown

So internet politics is another risk to backup strategy.