Tunisia and Egypt – and before them, Ukraine, Moldova, and Iran. Arguments still rage over the impact of social media in these momentous events. Were these “Twitter Revolutions,” as many have been eager to proclaim them, made possible by a new form of connectivity?

Or should we heed instead the warnings of public intellectuals like Malcolm Gladwell, who insists we’ve put the medium ahead of the message, and dismisses the twittering classes as voyeuristic cyber cheerleaders with weak ties and shallow commitments to the political movements they advocate. Should we read the sober if cynical Evgeny Morozov, a young Belorussian who challenges social media “slacktivism” and warns that tools like Twitter, Facebook and YouTube are as effective in rounding up dissidents as they are in marshaling them into the streets?

There’s been an immoderate rush to chalk these things up to social media, and it’s nothing new.Twitter users were quick to proclaim the death of traditional reporting because people can tweet about events – earthquakes, demonstrations– before the wire services can. Twitter triumphalism, whether vis-à-vis authoritarian regimes or authoritative old media, is foolishly hubristic. And it’s true that social media aimed at social good is too often full of empty feel-good gestures. Turning our Twitter avatars green to show our solidarity with Iranians, or changing them to black to show everyone we’ll be turning our lights out for an hour, is a kind of T-shirt and bumper sticker politics with very little real impact.

That said, it’s also too easy to be dismissive of social media’s power. It goes far beyond the “empowered consumer” who, with enough followers on a microblog, is assured of better customer service from the banks and airlines who now routinely monitor chatter out of fear of reputational damage. The Internet has emerged as a bona fide public sphere in Chinese life, and it’s had a powerful social impact. Online forums, social networks, and newer forms of social media have been setting the agenda for the national conversation in China, shining a light on official corruption and other malfeasance, and lending unprecedented potency to the voices of ordinary netizens. While more formal, institutional channels would be preferable, an officialdom obsessed with online public opinion is at least much more responsive than in years past.

In the last month, right here in China we’ve seen Sina’s popular microblog Weibo put to remarkable use to address a social evil in our midst: the thousands of children who are kidnapped and put to work as beggars by unscrupulous criminals. The activist social-scientist Yu Jianrong launched a campaign asking netizens to photograph beggar children and send their pictures and details – dates and places – to his Weibo account, where he can upload them to a database for parents to help locate their missing children. Already hundreds of thousands are following the account, and pictures are pouring in, with highly publicized reunions already taking place. Police all over China are suddenly taking a new look at this problem, and have begun their own initiatives using microblogs to reunite families.

It’s something that Western expatriates can take part in, too, and actually make a difference. After all, beggar children approach foreigners preferentially. Beijing resident Charlie Custer, a blogger and documentary filmmaker working on a project about kidnapped children, is using his Twitter account @ChinaGeeks as a clearing house for foreigners who don’t use Weibo and want to help out with beggar- kid pictures. You can also send pictures to Bill Bishop (@niubi), and they’ll get to Yu Jianrong – and hopefully to their parents.

What Yu Jianrong and others are doing is not without controversy. Some prominent bloggers have criticized this online vigilantism as another form of the “human flesh search” that has resulted in wrongful persecution at times. But it’s hard to fault this initiative when it yields results. It proves that, used judiciously, social media really can do social good – and that it’s not only about toppling tyrants.