This is according to a report released Monday afternoon by a team of NBC journalists, including Glenn Greenwald who is listed as a special contributor, based on NSA documents exposed by whistleblower Edward Snowden.
The report unearths a slide presentation (Psychology - A New Kind of SIGDEV) by British intelligence agency GCHQ, given to their U.S. counterparts in August 2012, detailing their "Squeaky Dolphin" program that allows them to glean information from,
"the torrent of electronic data that moves across fiber optic cable and display it graphically on a computer dashboard," according to the NBC article.
In the slides, published by NBC, GCHQ officials tout their abilities to conduct,
"Broad, real-time monitoring of online activity of: Youtube Video Views, URLs Liked on Facebook, and Blogspot/Blogger Visits."
"once the information has been collected, intelligence agencies have the ability to extract some user information as well."
GCHQ is apparently not the only agency wielding these online surveillance tools.
"According to a source knowledgeable about the agency's operations, the NSA does analysis of social media similar to that in the GCHQ demonstration."