Be aware, though, that DropBox' claim to fame is convenience, definitely NOT security! Quite the contrary! Let me explain:
a lot of people have copies of important files and documents in their DropBox. Like credit card, bank account, and passport details, lists of passwords, tax returns, etc. etc. Because it is of course very convenient to have those available even in extreme circumstances when you have nothing else left (like your travel bags have been stolen, or your house has burnt down...). They use DropBox as a virtual 'USB stick', which you therefore cannot physically lose (DUH!), and is consequently always available.
However, you should be aware that, for starters, Messrs. DropBox, Amazon, NSA, CIA, and FBI have full access to whatever you've stuck in your DropBox! Also, those 'clouds'/databases become prime targets for hackers and thieves because of their sensitive content. And databases get lost, stolen, and hacked into all the time of course! Read the paper!
So, yes, DropBox is very convenient, but it is NOT secure! So if you want to stick sensitive documents in there be sure you encrypt those before you drop them in!