Reprising a relevant comment:

The United States and allies do use the internet to spread Western culture and ideas, start revolutions, and kindle insurrection.

The United States CIA attempted (and nearly succeeded) in inciting a revolution against Castro by pretending to be a series of grassroots movements on a Twitter-like platform and by inciting anti-administration feelings within the Cuban population. That was earlier this year.

"USAID effort to undermine Cuban government with fake ‘Twitter’ another anti-Castro failure" [1]

The United States has an ongoing effort to use Internet media to 'deradicalize' the next generation of Middle Easterners and actively manipulates public opinions in Jordan, Cairo, Syria and other Middle Eastern states. Here are some quotes from one DoD MINERVA paper:

"...it is imperative that we develop empirically-based procedures for countering messages that promote violent extremism and anti-Western beliefs..."

"...Neural predictors of Twitter impact in Cairo (UCLA & Egypt). Our prior work (Falk et al., 2012), indicates that neural responses of a small group can predict which persuasive messages will be more successful in mass media campaigns..."

"... Defense Group Inc. already tracks Twitter trends specific to Egypt and will identify which of the selected Twitter topics went on to be highly influential over the next month and which did not..." - Matthew Lieberman, UCLA, September 30, 2012, Department of Defense MINERVA Initiative [2]

Here's one US company that does it. MARAYA MEDIA - "Driving Intelligent Dialog". [3]

The United States engages in targeted mass media and social manipulation to stir dissent in target nations, and to quell dissent where destabilization would hurt policy objectives.
The DoD's MINERVA project specifically looks to understand the cultural components of stability of various countries and mechanisms to encourage or disrupt that stability. Among a great number of social studies you will find DoD research on how to seed information inside of specific Asian countries, including China, for the targeted introduction of instability. I will leave speculations of possible connections to the Hong Kong protests to the reader. [4] During the Iraq war US officials were known to detain Iraqi journalists and bloggers and force them to write articles in favor of the American efforts or to spread misinformation useful to ongoing campaigns. The CIA purposefully slipped misinformation into American media outlets to fool counterinsurgents who were reading American media (the infamous "Fallujah PysOp").

This should not come as a surprise given the history of the US: The United States and allies are known to target media in other countries to stir dissent. Radio Free Europe, "Voice of Iraq" (cough American), the Lincoln Group infiltrations and partnerships, etc.

But now with global interconnectedness it is easy to set up 'foreign media', blogs and other politicizing content to influence other nations' populations.

In the past decade it has become a global issue.

This year Egypt sentenced Al Jazeera journalists that they believed were partnered with geopolitical interests of other states. Putin's administration is now requiring bloggers to register if they have a certain number of readers, so that his administration can curtail international influence. China blocks many American services including Facebook and Google. The usual story in America is that they are censoring free speech. The truth is that they do not want foreign influence to destabilize their population and that they do not want their citizen's data in America's PRISM program (there's a reason it's called the FISA "Foreign Intelligence Surveillance Act" court).

The Snowden revelations showed us how intelligence agencies are involved in PsyOps - the term for 'psychological operations' used by the CIA and others.
The GCHQ's BIRDSONG/BADGER/GATEWAY/SLIPSTREAM/ETC and partnership with the NSA are used to influence online polls, discussion forums and to vote up and down content that aligns with policy goals. [5][6][7] The giant meta-data graph created by the NSA is also particularly valuable for 'influencer' and 'social contagion' analysis (leaks showed they do use it to understand internal chain-of-command and organization structure for target selection). It's why metadata matters. A nice illustration of this is the article "Finding Paul Revere."

And so we have issues here with the use of targeted social influence in America as well. First there are instances where other countries are trying to incite disruption in the US - the US wants to study and curtail it. [8]

A number of journalists have called out that the state has been extremely aggressive to dissenting opinions, even to go so far as labeling current policy on the issue "War on Journalism". American officials have exported a number of journalists with Middle Eastern descent and journalists like Ayman Mohyeldin have been pulled from Gaza and other conflicts when reporting has erred on the side of other state interests. The crackdown on journalism is worth another post I don't have time to write.

Just look at how central a role controlling internet dialog is for running a modern US presidency. A Google search for "Obama internet campaign" [9] results in headlines "How Obama's Internet Campaign Changed Politics", "How Obama won the internet", "Barack Obama and the Facebook Election", "Propelled by Internet, Barack Obama Wins Presidency" - this isn't because of grassroots discussion but because both Obama and McCain (and Romney before him) had cyber centers in control of internet PR engaging tens of millions of dollars in Twitter messages, etc.

You can nudge public opinion by bombarding them with an influx of the same message, slightly disguised in one way and then another. The MINERVA program has plenty of good reading with regard to this. Anyway, the USG does this overseas and, to a limited degree (you decide how limited) presidential campaigns and journalistic partnerships (anyone want me to write a blurb on that...?) have them doing it inside the United States as well.

[1] http://www.washingtonpost.com/lifestyle/style/usaid-effort-t...

[2] http://minerva.dtic.mil/doc/samplewp-Lieberman.pdf

[3] http://www.marayamedia.com/company.php

[4] https://firstlook.org/theintercept/2014/02/24/jtrig-manipula...

[5] https://firstlook.org/theintercept/2014/02/24/jtrig-manipula...

[6] http://www.theguardian.com/commentisfree/cifamerica/2011/jun...

[7] http://www.dailykos.com/story/2011/02/16/945768/-UPDATED-The...

[8] http://www.washingtonpost.com/opinions/truthy-project-is-unw...

[9] https://www.google.com/?q=obama+internet+campaign

Comment reprised from here: https://news.ycombinator.com/item?id=8709976