Iranians by the thousands Tweeted, Facebooked, blogged, video streamed and posted on scores of Web sites to share the events with the rest of the world, thwarting government attempts to censor coverage of the post-election violence.
Twitter in particular appeared so powerful that the U.S. State Department even asked the micro-blogging service to delay a scheduled network upgrade to ensure Tweeting Iranians wouldn't lose access.
But while Twitter and its new media cousins have given millions of people around the world the unprecedented ability to speak out and quickly organize against repressive governments, some experts caution that social media doesn't only benefit the social activists.
Authoritarian regimes in Iran, China, Egypt and elsewhere have already become equally -- if not more -- social media-savvy, and the consequences of that reality could significantly hinder efforts to democratize digitally, experts say.
"I'm not sure we understand the implications of building public spheres," said Evgeny Morozov, Yahoo! Fellow at Georgetown University's E.A. Walsh School of Foreign Service.
In a U.S. Helsinki Commission hearing on new media in authoritarian regimes, Morozov last week warned that new media "will power all political forces, not just the forces we like."
Despite efforts to encourage the growth of pro-democratic groups online, he said research into the blogospheres in Egypt, Palestine and Russia suggest that the Muslim Brotherhood, Hamas and groups of Russian nationalists and fascists are among the most active users of blogs and social media.
"Blind support for promoting blogging and social networking may have a lot of very unpleasant unexpected consequences," Morozov said.
While it's true that governments may have lost some power to Internet-based modes of communication that empower many voices, he said authoritarian regimes have benefited from those same communication channels in other ways.
"The Internet has made it much more effective and cheaper to spread propaganda," Morozov told ABCNews.com.
New Media Can Give Appearance of Openness
In Russia, the government befriends new media entrepreneurs who spin online conversation in the government's favor. The Chinese, Morozov said, have created a "50 cent party" composed of thousands of people across the country who get paid 50 cents for each comment they leave online.
For some authoritarian governments, new media can be used to give the appearance of openness and legitimacy.
In a piece written earlier this year for the human rights blog openDemocracy.org, Babak Rahimi, a professor of Iranian and Islamic Studies at the University of California, San Diego, wrote about the "politics of Facebook" in Iran.
Despite blocking a number of dissident Web sites ahead of the presidential election, in February Iranian authorities unblocked the popular social networking site Facebook. Why would the state unblock Facebook while limiting access to other Web sites?
Part of the reason could be to encourage younger people to vote, thereby boosting electoral participation and signaling state legitimacy, Rahimi wrote.
Another reason could be to identify dissenters.
"By unblocking Facebook and creating a false sense of open and fair elections, the intelligence services are able to monitor the activities of dissidents who may feel more comfortable to express their views on Facebook," he wrote.
But the primary reason, Rahimi continued, was so authorities could show off their strength as a legitimate power.
"By conceding small amounts of liberty, the regime also hopes to gain approval for its 'progressive' nature," he said.
Morozov said that new media has also made it easier for repressive regimes to identify dissenters. Instead of employing hundreds of people to read published material, rulers can automate the process with computers programmed to search for keywords.
The Beijing-based TRS Information Technology, a search technology and text mining company, helps China control public opinion by using keywords to search for subversive content, the Financial Times reported earlier this year.
A marketing manager for the company told the Financial Times that it was starting to sell services that allowed monitors to track comments and forecast public opinion. He also said police use the technology to focus attention on certain groups of people, such as university student forums.
'Cat and Mouse Thing' for Activists to Stay Ahead
Though there are risks to opening up public spaces online, experts also say that with ongoing awareness of developments in new technology, progress is possible.
During last week's Helsinki Commission hearing, Nathan Freitas, an adjunct professor with the Interactive Telecom Program at New York University and developer of technology for protests, said there are numerous stories of Chinese, Tibetan and other activists being monitored via Skype, Yahoo!, e-mail and other online tools.
Still, he said that when activists protested for Tibetan independence during the 2008 Olympic games, China's efforts to block coverage didn't stop the protestors from broadcasting their activities. Digital video cameras, handheld computers and live streaming camera phones helped their protests succeed, Freitas said.
"It's a cat and mouse thing, staying one step ahead," he told ABCNews.com. Activists need to stay on top of a government's technical capabilities as well as its overall priorities. And the best use of new media for activists changes from country to country.
For example, given China's ambitious business aspirations, it can't block as much of the Internet as countries with more humble goals, Freitas said.
But a government's grand plans can also provide exploitable opportunities.
Although China may crack down on Skype, e-mail and other communication channels, because it wants to encourage small businesses, Freitas said devices like BlackBerries work well in China.
"The irony of the world is that everyone wants a piece of the Internet commerce cookie? These countries are promoting the people getting computer science degrees, so you're seeing the rapid rise of intelligence and capabilities within the countries themselves," he said. "If you can find the loopholes that tie in technology with commerce, it's kind of a sweet spot."