What's Trending: #Revolutionwhatrevolution?

When I recently discovered Twitter, I went from contemptuous to addicted in about three days. But one thing still puzzles me about the world's 10th most popular website: the notion that it's a revolutionary medium. The failed Moldovan rebellion of 2009 was probably the first to be dubbed the "Twitter revolution," but since then, Twitter has been credited with launching the Iranian uprising, Arab spring and London riots. Now it has supposedly prompted the African Union to hunt for the Ugandan warlord Joseph Kony, after an anti-Kony propaganda film spread through social media and was watched more than 100 million times. I confidently predict that the next revolution anywhere on Earth will be dubbed "the Twitter revolution."

Nontweeting readers may have formed the impression that the Twittersphere is devoted to summoning people to demonstrations in gray repressive capitals. In fact, "trending" items are usually celebrity deaths, goals in football matches or anything to do with the teenaged singer Justin Bieber. And what's true of Twitter appears true of computers in general. They are anti-revolutionary devices. The global addiction to computers is helping keep the world quiet and peaceful.

Every now and then, of course, social media do contribute to change. The Facebook page "We are all Khaled Said," named after a young Egyptian who died in police custody, helped galvanize protesters in Cairo's Tahrir Square last year. And bad activists use YouTube and Twitter too. "On the web one can proselytize for the jihad all day and night with friends from around the world," writes Jytte Klausen, an expert on terrorism at Brandeis University, and colleagues.

Mostly, though, computers produce quietism. Despite Occupy Wall Street, a striking fact of the great recession in developed countries has been the passivity of young people.

Historically, revolutions are made by the young: few of the Parisians who stormed the Bastille in 1789 came on Zimmer frames. And today's youth ought to be rebelling. About a fifth of under-25s in Western countries are unemployed. Their luckier peers are mostly either studying something that won't lead to much, working as underpaid interns or waiting tables. The best-educated generation in history is ceasing even to think in terms of careers anymore: entry-level positions in sought-after industries such as fashion and media are now typically unpaid. If that were me, I'd be angry.

True, there was a wave of rebellion: by one estimate, 900 occupations of urban public space have taken place in Western countries since last spring. However, from Oakland to Auckland the wave died. This was not 1968. Only in the much less Internet-penetrated Arab world did the young demonstrators persist. Of course, few Western youths quite want to topple their regimes, but there was an additional force keeping them off the streets: computers. Computers are the perfect narcotic, even better than TV, because you rarely sit around a computer with your friends. Occupy Wall Street quickly grasped that to keep its customers satisfied, it needed to install free Wi-Fi in New York's Zuccotti Park. The authorities quickly grasped that to deflate the occupation, they needed to seize the Wi-Fi gear.

Many young people today practically live with screens. A study by the Kaiser Family Foundation in 2010 found that Americans aged 8 to 18 were spending nearly eight hours a day on devices such as computers, smartphones and TV. The study's authors were stunned: they hadn't realized anyone could pack that much screen time into a day.

If you're watching a screen, you're probably not making revolution. The 300 million Chinese microbloggers are arguably the greatest anti-revolutionary force on Earth. Where were they a year ago, when the Communist Party was worrying about uprisings? In their bedrooms, blogging. Some of them blogged about politics.

It didn't change much. Sarah Nouwen, a law lecturer at Cambridge who studied the viral campaign against Kony, believes that, for many people, sending a political tweet is an end in itself. "It's something you can use to strengthen your moral CV," she says. "So if you tweet about Kony, you look and feel good." The tweeter may not fret much about what happens in Uganda afterward. This is what is known as "slacktivism": lazy support for causes.

Perhaps we should be grateful to screens. Some social scientists puzzling over the recent fall in violent crime in Western countries have formulated a new theory: many potential criminals are too addicted to their screens to go outside. After all, mugging, fighting in pubs and storming the presidential palace are leisure time activities. When you can spend your leisure time inside with a computer, why stand in the rain and harass passersby? The economists A. Scott Cunningham, Benjamin Engelstätter and Michael R. Ward argue that though violent video games make people feel more violent, the net effect of those games is to reduce violence because they keep potentially violent people home.

Still, if you have any minutes left in your screen day, come and make the revolution with me at @Kupersimon.