Apple's iCloud is a set of free new cloud services that work seamlessly with applications on your iPhone, iPad, iPod touch, Mac or PC to automatically and wirelessly store your content in iCloud and automatically and wirelessly push it to all your devices. (Business Wire)
Keep it off the cloud
All of the passwords, documents, grocery lists, and term papers that you have put into online storage – think Google docs, DropBox, iCloud – become part of the great Internet data lump.
If you don’t want certain information to be accessible to either hackers or government warrant, store it on your computer’s hard drive, or on an external USB drive, preferably an encrypted one.
Which brings us to our next recommendation…