Metadata are hints and details at what you have been doing or where you have gone. Many say they don't care but those people don't understand what metadata is. Think of letting someone know where you make every call and whom it went to makes me rather nervous. The counter argument to this is, people give away their info freely all the time, but these companies, do not have the ability to imprison me or to take away my rights. The NSA says they only do two hops, meaning If a friend called a terrorist then the NSA could call me because it is just TWO data points away from me. The issue is that most people have called a major business like Fedex or AT&T. This means that a "terrorist" could call FedEx and now everyone who has called Fedex is a hop away from being investigated, even though there is no real connection. This opens the possibility of huge swaths of people to be spied on or have their details kept. I recommend reading this article off of Boing Boing and to watch the interview below from PBS News Hour to understand a bit more about what metadata is and how is can be used. Remember, there may not be a use for your data now, but there may be one coming up soon.