today social media, facebook and the like, are critical to understanding social movements. >> reporter: the documents leaked by edward snowden and obtained by nbc news included a top secret presentation of a pilot program given to american intelligence officials by gchq, the british equivalent of the nsa. the slides show how british spies are able to tap into cables and pull encrypted high speed data, including youtube addresses. they analyze the information to answer critical questions. none of the data is gathered within the u.s., sources say, but americans who use these websites overseas may have their online activity monitored. the nsa say they operate within the law and do not spy on the social media activities of ordinary americans. civil liberties groups, among others, are alarmed. >> it's one thing to spy on a particular person who has done something to warrant a government investigation. but governments have no business