What Prism Knows: 8 Metadata Facts

Data traffic analysis could provide "megadata" intelligence agencies can use to cross-reference information using big data techniques.
5. What Location Information Does the NSA Capture?

Government officials have said that the 2015 Program -- also known as Mainway -- doesn't capture location metadata, and if it did, that might have Freedom of Assembly implications. But the NSA programs detailed to date in press reports have included not just Mainway and Prism, but also an Internet metadata collection program (Marina) and some type of telephone content interception program (Nucleon).

In his interview, Obama didn't touch on which NSA programs do record location data, leading The New Yorker to note: "There seems to be a shell game of reassurances, where what is meant to make us feel better about one program doesn't apply to another, or to how they work together."

6. Don't Stress over Meta-Data Collection?

How much metadata should the government be allowed to capture or use? "The drafters of the Constitution did not propose some absolute right to privacy; they ... saw privacy as a means to achieve a larger goal, to protect political liberties," said James A. Lewis, a senior fellow and director of the Technology and Public Policy Program at the Center for Strategic and International Studies, in a blog post.

His argument: if it safeguards people's political liberties, then capturing metadata is a useful technique. "The essential political rights are freedom of expression and assembly, freedom from arbitrary detention, and the right to petition the government for a redress of grievances," Lewis said. "If these four rights are protected, surveillance is immaterial in its effect on civil liberties."

7. NSA Focus: Terrorists, Nukes, Enemy Nations

Furthermore, Lewis said, while NSA might collect mountains of data, that's its charter, and in reality the agency reads almost none.

"NSA (and the larger U.S. intelligence effort) focuses the bulk of its attention on terrorism, proliferation, and a few hostile countries that threaten the United States and its allies." he explained. "These are the priorities; there simply are not enough analysts to look at much else."

8. Fears of a Surveillance State

But what of the potential impact of persistent -- and some might argue, excessive -- surveillance of innocent people? Without a doubt, the leaks have laid bare programs that many Americans have found to be overreaching.

"The programs of the past can be characterized as 'proximate' surveillance, in which the government attempted to use technology to directly monitor communication themselves," said the computer researcher known as Moxie Marlinspike, formerly CTO of Whisper Systems, in a blog post titled "We Should All Have Something To Hide."

"The programs of this decade mark the transition to 'oblique' surveillance, in which the government more often just goes to the places where information has been accumulating on its own, such as email providers, search engines, social networks, and telecoms," he said.

With persistent surveillance, Marlinspike said one fear is that by capturing so much information on U.S. citizens, a determined investigator could likely find some type of charges to file against a suspect, given that legal experts estimate that there could be almost 10,000 federal crimes on the books. "If the federal government had access to every email you've ever written and every phone call you've ever made, it's almost certain that they could find something you've done which violates a provision in the 27,000 pages of federal statues or 10,000 administrative regulations," said Marlinspike. "You probably do have something to hide, you just don't know it yet."