The British government can tap into the cables carrying the world's web traffic at will and spy on what people are doing on some of the world's most popular social media sites ... without the knowledge or consent of the companies. Documents taken from the National Security Agency by Edward Snowden and obtained by NBC News detail how British cyber spies demonstrated a pilot program to their U.S. partners in 2012 in which they were able to monitor YouTube in real time and collect addresses from the billions of videos watched daily, as well as some user information, for analysis. At the time the documents were printed, they were also able to spy on Facebook and Twitter. Called Psychology A New Kind of SIGDEV" (Signals Development), the presentation includes a section that spells out "Broad real-time monitoring of online activity" of YouTube videos, URLs "liked" on Facebook, and Blogspot/Blogger visits. The monitoring program is called "Squeaky Dolphin." Experts told NBC News the documents show the British had to have been either physically able to tap the cables carrying the world's web traffic or able to use a third party to gain physical access to the massive stream of data. Representatives of Facebook and Google, which owns YouTube, said they ... were unaware the collection had occurred. The NSA does analysis of social media similar to that in the GCHQ demonstration. In 2010 ... GCHQ exploited unencrypted data from Twitter to identify specific users around the world and target them with propaganda.