The Urban Dictionary defines "Slacktivism" as "the ideology for people who want to appear to be doing something for a particular cause without actually having to do anything." It's an apt description of those who click the Facebook "like" and "share" buttons for everything from neutering pets to resolving the European debt crisis. No need to spend a lot of time learning facts, mastering complex arguments, or organizing your friends and neighbors -- and you can leave your money in your wallet. Just retweet a 140-character analysis of federal spending and you can move on to the ball scores.

That's been the argument, anyway, of critics of the so-called "social media revolution." They see our newfound global connectivity as a passing fad at best, or, at worst, as yet another sign of our divisiveness and narcissism -- and to a large extent, they have a point. Much of the political expression on the Internet, if expressed "IRL" ("in real life"), would result in a punch in the nose, if not an arrest. Go to the "comments" section of most websites and it won't take long before you read the online equivalent of a drive-by shooting; the vicious, personal, and usually anonymous attack is the substitute for reasoned debate. There's also the practical question of how to mesh the political gears with social media. As one veteran politico once challenged me, "Explain how Twitter and Facebook gets somebody out of the Barcalounger and into the voting booth."

I'm living proof of the power of social media: On Jan. 20, 2009, it put me out of work. President Obama's 2008 campaign deftly utilized the emerging social media icons of the time -- YouTube, MeetUp, Facebook, and Twitter -- as means for millions of Americans to vent their frustration with the policies of my then-employer, President George W. Bush, and it played a central role in returning the Democrats to power.

From Cairo to Tripoli to Wall Street's Zuccotti Park, social media has reduced the cost and complexity of organizing mass numbers of individuals into a single, cohesive, political force. In the process it has redefined social activism. What's more, as it continues to evolve to develop new platforms, it creates new opportunities for political expression that become increasingly difficult for others to suppress. In 2009 the Iranian regime thought it could calm an increasingly rebellious populace by shutting down traditional media, but that was before the shooting of a 26-year-old female protester was captured on video, uploaded, and viewed by millions. At the height of the uproar, more than 221,000 Iran tweets were sent in just one hour. In one day, 3,000 Iranian videos were uploaded on YouTube, and 2.2 million blog entries were posted. The young woman, named Neda, had become the "cause," and social media, not traditional outlets, were providing the megaphone.

Later that year, a Tunisian fruit-stand owner named Mohamed Bouazizi was accosted (not for the first time) by police thugs demanding a bribe. They confiscated his wares; he complained to the government, which, as usual, did nothing. Bouazizi, age 26, doused himself with gasoline and set himself on fire. The day of Bouazzi's self-immolation, no one -- least of all Muammar Gaddafi, Hosni Mubarak, Bashar al-Assad, and Tunisia's Ali Abdullah Saleh -- had any idea of the upheaval that would result from the ideas, voices, and actions that were soon to be unleashed through social media. As word of Mohamed Bouazizi's brazen act of protest spread across the Middle East and throughout the horn of Africa, it caused an unprecedented wave of civil disobedience, public demonstrations, and strikes across the region. Social media had become the new soft weapon of democracy. Mubarak tried to pull the plug on the Internet, but repression couldn't keep up with the pace of technology as Google and Twitter deployed means to keep the Egyptian protestors' voices alive. Twitter introduced a new "voice-to-Twitter" service that allowed users to post by merely calling a dedicated phone number, and thanks to Google Translate, the messages from the teeming streets of Cairo soon became understandable across the planet. Social media may not have been the spark that set the fire, but it certainly provided the oxygen that caused it to spread.

While true that "slacktavism," online bullying, and unprecedented threats to our privacy are challenges, few could argue that social media has not vastly facilitated political involvement. The results have been impressive, if not always as dramatic as the Arab Spring. Consider the phenomenon of Joseph Kony, the brutal Ugandan guerilla leader who was the subject of an online video that was viewed by 100 million people worldwide. In the Kony case, 850,000 Facebook users clicked the "like" button. What resulted was the deployment of 100 U.S. advisers and 5,000 African Union troops whose mission was to hunt down Kony, achieving a goal that countless diplomats, non-government organizations, and journalists had failed to do in the previous 25 years.

People are using social media to hunt war criminals, win the White House, defeat an American House Speaker, change banking regulations, and overthrow dictators in Libya, Tunisia, Egypt, and Yemen. In each instance it was social media that facilitated broad-based social activism and empowered the aspirations of millions. Its power has just begun to be tested, but the evidence so far indicates that social media has successfully reinvented social activism.

This column was taken largely from Pfeifle's recent debate at the Oxford Union at Oxford University.