A yottabyte is one septillion bytes. To save all those bytes you need a data center as big as the states of Delaware and Rhode Island. It doesn't seem like much, until they tell you the price tag: $100 trillion.
In Utah, the National Security Agency is building a $2 billion storage facility that will house and analyze all forms of electronic communication...a potential yottabyte of everyone's (formerly) personal data. So how big is a yottabyte? CrunchGear puts it well: