It can happen in very visible ways. Protesters in Egypt have used social media sites, including Facebook and Twitter, to organize large demonstrations in the streets.
That followed a similar scene in Tunisia, where unrest ousted a president. A group of Tunisian natives even gathered at Facebook's headquarters in Palo Alto, California, to "thank Facebook for enabling our nation (both inside and outside the country) to freely share their opinion online, bridging our way to democracy."
But in China, it seems to be more subtle. We aren't talking about anything on the scale of anti-government marches... merely criticism of the Communist Party. Social media serves as an outlet for frustration.
Take the case of Li Qiming. He's the son of a senior Chinese police official. And he inspired a catchphrase for abuse of power: "My father is Li Gang."
Witnesses say that's what he shouted while allegedly trying to flee the scene of a drunk driving accident. It sparked outrage among China's netizens and inspired viral videos like this.
Li is accused of hitting two women with his car. One died. The Xinhua news agency reports he is now awaiting sentencing. He faces three to seven years in prison. Chinese media report Li's family already agreed to pay the victim's family 460,000 yuan. That's about $70,000.
The court proceedings have also met with some online outrage. On the microblog Sina Weibo (similar to Twitter), user Cheng Shi writes, "RMB 460k + 3 years of sentence = 1 fresh life! Is this really the end of the Li Gang case?"
Maybe. But it's certainly not the end of social media promoting social causes in China. The latest involves a migrant worker trying to go home for Lunar New Year. Chen Weiwei says he was unable to get a train ticket because other people, possibly with connections, cut the line. So he stripped to his underwear in protest. Netizens are showing the "naked man" some sympathy.