ALONGSIDE the horror, the banality. But for most parents of teenagers,aparticularly uncomfortable and recognisable kind of banality. There is Cho Seung-Hui,ex-Virginia State Universityundergraduate, standing in front of his digital camera. He's throwing gangsta shapes, exploitation-movie moves: gun in front of face, gun at temple, raised hammer, cap backwards, dead-eyed, bad boy sneer. Take a wander through the "my friends" links in any social networking site - Bebo, MySpace, YouTube or the cheapo webhosters like Geocities - and eventually you'll find pictures of some similar ghostface killa: emo-rock or hip hop as the website's soundtrack, scowls on a soft and pustular face, post-curfew nihilism in the bedroom or dorm.

Except this boy, for some reason, stopped playing with danger and murder, and became dangerous and murderous himself. The psychologists are on the case, swarming all over his biography: they'll find the syndrome, don't doubt it. But there is one other visual reference here that will not, and should not, be suppressed.

It's another young man in front of a digital video camera, striking his poses and brandishing his weapons, speaking in a similarly level and even tone. His enemies are more specific, his language much less fragmented, than Cho Seung-Hui. But they seem to share some common disgusts. One warns his viewers to beware of the media, "scaring the masses into conforming to their power and wealth-obsessed agendas"; the other berates "brats and snobs" for their trust funds, Mercedes cars and golden necklaces. One makes it clear that his "driving motivation doesn't come from tangible commodities that this world has to offer"; the other railsathistargetsthat"allyour debaucheries weren't enough to fulfil your hedonistic needs. You had everything".

The first set of quotes is from the videotape left behind by Mohammad Sidique Khan, one of the July 7 London bombers, born and bred in West Yorkshire. The second is from a DVD recording, compiled and packaged between two bouts of disciplined killing, on a placid academic campus in West Virginia.

Two young men, raging (with varying degrees of lucidity) against vast and powerful forces, seeking purity and clarity in the face of the messiness and trashiness of Western lifestyles, willing to use arms and weapons as their means of expression. And in both cases, the world must know the justification for their actions. Yet they can do better than a scribbled suicide note. Nowadays, you tube, therefore you are. Even if who you "are" is now an instrument of death: the spectacular destruction of your own identity, and others around you who are dragged into your own all-encompassing negativity.

And the maw into which all of this entropy, this warped masculinity, this extreme and fastidious withdrawal from the everyday pours? The media, the media, the media. Terrorists don't call them bombing campaigns,but"spectaculars".Psychopaths send their clips to NBC between sprees to ensure they make broadcast news.

The shared assumption is the existence of billions of viewers, a sizeable minority of the species in a staring position before flat screens.

In an age of mega-media, attention is one of our scarcest resources. And at least extremism, or exterminism, will definitely get us watching.

Yet of course, we must set these two dangerous young men apart. Their murderous deathsmightbothneedthemediato complete their meaning. But are their motivations quite the same?

Khan was a suicide bomber, putting his lethality in the service of a political and religious project. And as the Univeristy of Chicago's Robert Pape has shown, in his recent global study of suicide bombing since 1980, the over-riding aim is "to compel countries to withdraw military forces from territory the terrorists perceive as occupied".

On the bombers themselves, Pape continues: "Very few fit the standard stereotype of a depressed, lonely individual on the margins of society seeking to escape some wretched existence. That is, very few are suicidal in the ordinary sense of that term. Instead, most are socially integrated, productive members of their community."

The Oscar-nominated film Paradise Now shows exactly this process. One bomber fails his mission because of the tug of personal relationships; another succeeds because he submits his ego to the collective injustice inflicted on his people. And both bumble their way through the necessary martyr videos, failing to remember their lines, holding their guns inexpertly.

We may think that Wilfred Owen put paid to Horace's maxim that "dulce et decorum est pro patria mori" (it is sweet and becoming to die for one's country). But only a month ago, the UK's Air Vice Marshal David Walker asked his pilots to consider the "kamikaze scenario" in which they would use their aircraft as human bombs if their weapons had failed or been used.

All these discussions about murderous suicide take place within communities and institutions, themselves intimately connected to politics and history. If that context changes, then the individual's intent may change too: the act might lose its significance, and thus be stepped back from.

Yet when we think of Cho Seung-Hui, so far as we are currently aware, we hardly find him on the frontline of any struggle, other than with his own alienation from campus life, or with his own internal demons (possibly made even more furious by autism), or perhaps simply with the pains of becoming an adult. As I watch his whiny little videos and read his sprawling, typing-not-writing, both of them diligently recorded and produced over the preceding weeks, there are two cultural memes I can't get out of my own head. One is a line from the classic US college band Ben Folds Five: "Will you never rest/Fighting the battle of who could care less/Unearned unhappiness/That's alright I guess."

Unearned unhappiness. That's what my own college-bound teenaged daughter and her pals would call "pure emo". We must accept that there might have been some failure of pastoral care in Virginia Tech around Cho: teachers referred his mental condition to the university authorities, psychiatric reports were on file.

But it's also difficult not to read his statements as echoing the outpouring of immaturity now accessible through the social web. Disturbingly, Cho's manifesto reads like one long entry on a Goth's LiveJournal, as much as it demonstrates evidence of madness. How could any student liason officer identify the potential killer in the emo hordes of modern student life? How could you trace the link from ironic to psychotic?

Yes, as commentator Roy Greenslade points out, we are operating a media hierarchy of death here: 32 dead as a result of one crazed student, in the same day as 200 die in one act of carnage in Iraq, and the headline coverage is wildly incomparable. It would be easy, an act of "closure" as they say on the American newshours, to categorise this as the kind of occasional eruption of delirium that besets otherwise stable, cohesive, functioning Western societies.

Many news reports have cited Charles Whitman's clocktower shootings on August 1, 1966, where he killed 15 at the University of Texas in Austin. It was only slightly easier for the ex-marine Whitman to buy his weapon from the Sears department store, than it was for the humanities student Cho to get his material from the local gun shop.

Cho Seung-Hui explicitly put himself in the lineage of "martyrs like Eric and Dylan": almost certainly referring to Eric Harris and Dylan Klebold, the two teenagers who murdered 12 students and one teacher at Columbine High School, almost exactly eight years ago. And there is no more tangled matrix of neglect, media culture, technology and male alienation than Columbine.

The lessons of Columbine, brought into relief by Cho's atrocities, are more uncomfortable than ever. The most acute parallel is the way both sets of killers easily found the perfect cultural scripts through which to express their nihilism - and moreover, rehearsed and recorded these fixations. Harris and Klebold left recordings from their school video-production course, in which they debated whether Spielberg or Tarantino would be the best director to shoot their massacre. Apart from videoed mutterings that sound like out-takes from a David Fincher movie (maybe more Fight Club than Se7en), Cho also struck weapon poses that mirrored exactly some scenes from the notorious Asian gore-fest Oldboy. (He even saved his manifesto as a PDF document: good, helpful student.) But there are crucial distinctions here. Harris and Klebold sit almost precisely between the suicide bomber mandated by community and ideology, and the terrifying subjective isolation of Cho. They self-identifiedwitha"geek"subculture, standing up against the preppy and "Jock" (sporting and achievement) ethos that dominates American high schools. Kids quoted in the New York Times just after the event startled adult reporters with comments like: "I would never personally do anything like that, but it did take guts." And: "Even though I would never take someone else's life, maybe it will make people think before they open their mouths next time." The principals of Virginia Tech may take some consolation from the fact that Cho was such an isolate: what might have happened, had he been able to gather some fellow "martyrs" around him?

Martyr to whom? For what? How pathetic is this language? Again, it's tempting to downgrade the whole affair, reducing it, as one commentator did last week, to a "routine school misfit revenge". If a republic of emollience like Canada can also experience similar campus atrocities - the Montreal shootings of 1989 and 2006 - then perhaps this should be attributed to social vulcanism: the occasional eruption of fiery chaos through the crust of the everyday, only serving to show how well-ordered Western life really is. Back to class, everyone: show's over.

But is the show ever over? In 1999, media analyst Thomas De Zengotita wrote brilliantly on Columbine, asking that we consider our response to a society in which the "distinction between action and performance, and reality and representation, is eroding at every level of our lives". Yet the problem is that we are not coping very well withthesystematicerosionbetween fantasy and reality that a media-dominated society generates. We don't exist in a state of playful bliss, where our affluence and our toys allow us to live like latter-day techno-hippies, our imaginations shaping our lifestyles in pleasing social patterns. (For a starry-eyed version of this, read Iain M Banks's "Culture" science fiction novels).

No, it is 2007, and we are still mostly being ordered about - by big institutions, by ambitious politicians, by career expectations, by nationally-unifying "wars" on this, that and the other. Yet at the same time, the infernal desire machines of media capitalism still whirr, still stream utopian longing at us, inducing unrequitable affluenza and status anxiety, 24/7. We often don't dare ask the question, though the recent politics of wellbeing - led by psychiatrist Oliver James - is beginning to raise it. Does consumer capitalism make us mentally ill?

"The more enveloping and penetrating these stimulations and routines," wrote Zengotita, "the more uniform and centreless the settings of our lives What else should we expect but occasional psychotic eruptions on such a vast plain of disengagement, sustained by an economy devoted to simulations?"

Was Cho one of these eruptions? In the halls of Virginia Tech, sealed into his headphones and fused with his screens and thoroughly disengaged, did he lose the battle of who-could-care-less? Perhaps he was an example of what German poet Hans Magnus Enzensberger calls "the radical loser".

Bewildered and defeated by the contradiction of our times - between the equality he is supposed to feel as a citizen, and the inequality that he really feels when he looks at advertising and television - the radical loser confuses two complaints in his (and it's usually his) mind: both "it's my fault" and "the others are responsible".

Enzensberger continues: "These two claims are not mutually exclusive. On the contrary, they reinforce each other. The radical loser is unable to think his way out of this vicious circle, and it constitutes the source of his terrible power The only way out of the dilemma is to fuse destruction and self-destruction, aggression and auto-aggression.

"On the one hand, at the moment of his explosion, the loser for once experiences a feeling of true power. His act allows him to triumph over others by annihilating them. And on the other, he does justice to the reverse of this feeling of power, the suspicion that his own existence might be worthless, by putting an end to it."

Read again the weird confusion of self-loathing and blame in Cho's text, and that seems about right.

We often rise in the mornings, and perplexedly face a world where people seem willing to explode themselves and others daily. But the Virginia shootings, post 9/11, provoke some contrarian thoughts.

We may have more chance of stopping suicide bombing in the Middle East, and its overspill onto our territories, than we have of preventing campus, community or schoolyard massacres in the developed world.

The former is, almost entirely, a desperate political tactic, as the scholarship shows: by properly addressing our geopolitical commitments, its dangers will be lessened. The latter, it seems to me, is the savage price we will very occasionally have to pay for the open-ended, intrinsically stressful societies we have constructed in the West. (And lest we think we are safer up here,inthesemi-Scandinaviannorth, remember Dunblane.) In terms of young males, it it likely to be occasional rather than regular. The long-term statistics on youth crime, in the UK and US, continue to be counter-intuitive. The US Department of Justice shows victimisation rates cut by half, from 1973 to 2003; non-lethal crimes with firearms down by over 50% from 1993 to 2003. In the UK, a recent Nacro report confirms a more than 40% drop in risk of victimisation rates since 1995. Zengotita notes that in the 1950s, male gangs used to take their disputes to the car park (a social behaviour paralleled in the UK): now, the aggression gets virtualised, into the slicing and dicing of computergames.Somegames-industry advocates have even correlated a precipitous drop in youth violence with the predominanceofconsolegameslike PlayStation and Xbox.

If all the tensions of young male frustration are going virtual, the violence involved must be channelling somewhere, corroding character in other, subtler ways. Part of that subtle effect may be that we will not be able to predict when someone will unravel or snap. At what point will a modern individual be unable to maintain the poise and balance between opposing elements that constitute sanity and normalcy in the developed world - that is, between the dutiful, productive citizens we're told to be, and the "hedonists" (Cho's words) we are stimulated into being?

An obvious route is to question the very omnipresenceofmedia,whichnow actively invite everyone to enjoy their 15 minutes of "celebrity", through every available means of communication. Does this create the widest-possible stage for narcissistic nihilists like Cho - as Enszenberger says, never more alive than when blowing themselves and others up, anticipating their macabre stardom in the subsequent inferno of news reports? The novelist Lionel Shriver argues that news organisations should refrain from covering every gory and obsessive detail of atrocities, to avoid raising the possibility of "copycat" crimes from similarly pathological loners.

Yet we should be sceptical about constraining the media from showing the details of extremist acts. Would our scepticism about our involvement in the Middle East be so acute without the digital stills of casual torture from Abu Ghraib in our minds? We can rail at the media for not giving due weight to atrocity: but we can hardly complain about its inherent tendency to bring us the worst. Without the oxygen of publicity for all, our democracies choke and die.

But liberal democracy was always the least worst system available: and no-one could ever say that the tensions and complexities it embodies don't have costs. Cho was a melodramatic, off-centre emo kid who went very, very badly wrong - but the actions he performed are not in themselves inexplicable. They may, however, be completely unpredictable, under our current social arrangements. And thus, unless we have a greater appetite for systemic change than I can perceive, unstoppable.

Pat Kane is the author of The Play Ethic (