Western intelligence agencies secretly use social media to inflict dirty tricks on enemies and to manipulate the public’s political perceptions, according to a major investigative report last week by Glenn Greenwald.

Based on documents provided last year by former NSA and CIA employee Edward Snowden, Greenwald published How Covert Agents Infiltrate the Internet to Manipulate, Deceive, and Destroy Reputations in cooperation with NBC and via the First Look Intercept site.

“I want to focus and elaborate on the overarching point revealed by all of these documents,” Greenwald wrote Feb. 24. “Namely, that these agencies are attempting to control, infiltrate, manipulate, and warp online discourse, and in doing so, are compromising the integrity of the internet itself.”

Greenwald is shown in a file photo describing the implications of secret western national security documents that Snowden took when he worked as an NSA contractor.

The revelations extend via new documentary evidence in a more visible way similar dirty tricks previously reported. In 2011, for example, the hacktivist group Anonymous released hacked documents from a federal contractor showing elaborate plots to smear Greenwald and other journalists — and also to create phony sock puppets to gather information via social media.

Lee Fang of Think Progress first reported, for example, that “Holly Weber” was an avatar created for Facebook by contractors, and not a real person. I reported the implications of that story in Feeling Friendly This Week? Beware, and also in my recent book, Presidential Puppetry: Obama Romney and Their Masters.

This week’s revelations have sparked a wider ranging debate on the extent of Western intelligence to use social media — which can includes such platforms as Facebook and Wikipedia — to distort the operations of users, and undertake propaganda and other political operations.

We have been writing separately about potential intelligence uses to use Wikipedia through its network of anonymous editors to shape public perceptions. Aside from the intelligence agencies, the Naval War College in Rhode Island is a major center for such operations with the traditional and social media n the United States.

Related issues arising last week included how much prominence social and traditional media would grant such revelations. Reddit, for example, banned links to the Greenwald story form one of its major distribution platforms.

Greenwald said the report was based on four classified GCHQ documents presented to the NSA and the other three partners in the English-speaking “Five Eyes” alliance that includes the US, UK, Canada, Australia and New Zealand. The GCHQ is the UK’s equivalent to the NSA. The document below is from a stash of secrets within the Joint Threat Research Intelligence Group, JTRIG, a previously secret unit with the GCHQ.

Greenwald described the importance as follows:

“By publishing these stories one by one,” he wrote, “our NBC reporting highlighted some of the key, discrete revelations: the monitoring of YouTube and Blogger, the targeting of Anonymous with the very same DDoS attacks they accuse ‘hacktivists’ of using, the use of ‘honey traps’ (luring people into compromising situations using sex) and destructive viruses.”