CONTINUES WITH cynthia McFadden. Reporter: Maybe the strongest statement yet about the power of social media, the head of the largest christian church on earth, the one that uses puffs of smoke to... See More
CONTINUES WITH cynthia McFadden. Reporter: Maybe the strongest statement yet about the power of social media, the head of the largest christian church on earth, the one that uses puffs of smoke to announce a new lead signed on this year to twitter. The pope is sort of like the coolest pope ever, really. I mean, this guy does selfies, he is totally on trend. Reporter: But the pontiff's flock of followers at 3 million has a long way to go to catch up with the world's most popular tweeter -- katy perry, who has 48 million fans. But it isn't just the pope and pop culture being shaped by social media. From syria and those viral cell phone images appearing to show a chemical weapons attack to kenya, where a four-day siege at the westgate mall left 67 dead, and witnesses posted events, some in real time, on youtube, twitter and instagram. The line between reality and hollywood is so blurred right now. Like, if you told me that that was some movie by katherine bigelow, I would believe it. ReporteN FACT, SOCIAL Media has given the public an unprecedented role in detective work. During that tragic day at the boston marathon, crowd sourcing became the latest tool in crime solving. There has to be hundred if not thousands of photographs or videos or observations that were made down at that finish line. The ability to piece together through peoples' instagrams and twitter feeds -- what they're saying, what they're seeing, the ability to upload video very quickly -- not only do you have surveillance cameras, but you turn everyone into their own surveillance camera. Reporter: People stepped up, which was both a blessing and a curse. In boston, several people with backpacks were identified as suspects who turned out to be totally innocent. Internet can be very good and it can be very dangerous. I hope we all learned a lesson by that. Reporter: One man learned a very hard lesson this year. He thought he'd met the woman of his dreams online. Manti te'o was a football star at notre dame, now a san diego charger. He talked to katie couric. She was just that person that I turned to, the love of my life. Reporter: Except she didn't really exist. Manti te'o was the victim of a terrible catfish. What is so creepy about that is his best friend is the one that was catfishing him. At that time, didn't know i didn't know it was just somebody's prank. Reporter: Nobody wants to be catfished, but it seems everybody wants to be noticed. When the stadium went dark at this year's super bowl, the makers of oreos quickly tweeted, "you can still dunk in the dark." Not to be outdone, walgreens boasted, "we do carry candles." And speaking of self promotion, its official 2013 is the year of the selfie. The use of the word has increased 17,000% this year, even making it into webster's dictionary. I couldn't help taking a few with robin. Bret erlich's favorite selfie of 2013? ♪ geraldo rivera's topless shot. You're a 70-year-old man. Probably shouldn't be shooting selfies like that. Reporter: In 2013, seems everyone was self-obsessed, even the first family, who you think might have had enough photographers by now. There's a great animated gif of sasha and malia taking a selfie, and michelle obama just looking back and going, "you're not taking a selfie, are you?" Reporter: The president raised eyebrows taking a selfie at the mandela memorial. But some people's self absorbs ion has gone to absurd, even deadly levels, like people who drive while snapping them. You not want that in your obituary. Driving while taking a selfie at 08 miles an hour. Reporter: So there's the stuff we put out there intentionally, wisely or not, but how about all the ways in which we are being watched without knowing it? Just a few weeks ago, we learned the national security agency is tracing 5 billion cell phone locations a day. Imagine what else the nsa can do with a $10 billion budget and a 35,000 person staff. One person asked that question very loudly this year -- edward snowden. Traitor to some, patriot to others. My name is ed snowden, I'm 29 years old. Reporter: A young data technician working at the national security agency. I, sitting at my desk, have the authority to wiretap anyone, even the president. Reporter: Setting off a firestorm when he leaked information about the u.S. Government's sweeping surveillance program. Its an international chase tonight. Edward snowden is flying to moscow. It's clear that russian officials have no plans to stop him here. Edward snowden had a certain "where's waldo" feel to it, at least in the very beginning. Great harm has been done here. Reporter: Snowden gave then "guardian" reporter, glenn greenwald, the story of the year. We talked to him from rio. He e-mailed me roughly two dozen documents or so. And I remember barely being able to breathe the first time I read through them. Reporter: Among the docume proof that the u.S. Government was spying on regular americans citing national security. You don't have to have done anything wrong, you simply have to have eventually fallen under suspicion. From the very beginning, once you started looking at the documents, were you persuaded that this was indeed an enormous story? But once I saw the full archive that he provided, the thousands and thousands of top secret documents, that's when i knew that this was the most significant leak in national security history. More to come? Definitely more to come. Still a lot of very significant stories that are yet to be reported. Reporter: Just imagine what's left to come out in 2014. So maybe the message of the social media monsoon of the year -- just like your mother said, nothing you do is ever really secret. ♪ Announcer: Next, the song
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