Can "The Cloud" keep anything secret?

I'm not fully up to speed on how "The Cloud" works internally, but wanna bet it can be hacked?  And since it's on line 24/7, the hackers can keep hitting it until they get in.  Whereas I can unplug my computer from the internet, and nobody can get at it short of breaking and entering.  If I was really serious, I'd burn the stuff to DVD and hide the DVD's in the house.  And disable Windows auto run so a single thumb drive insertion doesn't put a root kit on my system.