This is a celeb leak the likes of which have never been seen. Usually you have leaks of a few celebs or a few pics of one celeb but this is many pics of many man celebs. It's pretty crazy
That's what happens when you keep your files on the internet.
Definitely, you would have to be naive to trust them to keep your stuff private in the cloud. If you want to back up private stuff online, you need the folders encrypted.
Take Skydrive for example. All that is needed to gain access to that, is access to your email account. And how often do people get their email accounts hacked? Far too frequently I think.