Ljs: Sky Atlantic and the box-set era

I was watching the serial-killer drama Dexter the other day, and wondering about its politics. Dexter, in case you haven't seen the show, is a killer who kills killers: he uses his fondness for kidnapping, torture and mutilation to do good, sort of.

What is this show trying to tell us? Is it a slyly anarchic subversion of the moral certainties of the traditional detective story, showing us the blood on our own prurient hands? Or is it the ultimate reactionary fantasy, whereby wrongdoers are cruelly eviscerated and liberals can't protest, because the guy doing the evisceration has "issues"?

I wondered about throwing the question out to Guardian readers in the hope one of you could figure it out, so that I could get on with enjoying Dexter's vicious sadism with a clear conscience. But then I remembered that the Dexter I was watching aired in 2006, and any of you who are interested will have made up your minds long ago and moved on to speculating whether Don Draper is a misogynistic alcoholic prick ? or a soul in torment.

That is the curse of the box set in particular, and the digital age in general. What's the point of talking about telly when nobody's watching the same thing at the same time? Thanks to the box set, Sky+, iPlayer and so on, in the space of just a few years the way we watch TV drama has been transformed. Its vocabulary ? "tune in", "stay with us", "after the break", "previously on . . . ", "see you next time", "appointment television", and even "broadcasting" ? speaks of something shown fleetingly to a large number of people at the same time.

But that's gone. It is now, effectively, impossible to miss anything. Patton Oswalt, the US standup, has coined the pleasingly Star-Wars-sounding phrase Etewaf for this phenomenon: Everything That Ever Was ? Available Forever.

Once, nations wondered as one who killed JR. They flushed their toilets as one during the ad break in the final episode of M*A*S*H*. They rejoiced as one in Times Square when Friends ended. Now they tremble in fear of overhearing a spoiler from a colleague who's watching season two.

Not only is much of the great television of the age being watched long after the event, it is specifically designed with the box set in mind. Sitcom and soap take a back seat to HBO-style drama serials: self-contained episodes framed in a series-long plot arc. In some ways ? not least their addictive quality ? they resemble levels in a computer game: for "just one more go", read "just one more episode". No disrespect intended: we're living through a golden age of these things.

There's The Wire, of course, the first significant work of art of which it could be said that literally everyone who saw it wrote a column about it for this newspaper. There's Lost, whose title indicated what happened to your life once you'd watched a few episodes. There's House, whose title indicated what you seldom left once hooked. Meanwhile, The Sopranos was about as easy to get out of, once you were in, as the mafia. And The West Wing was as addictive as power. Go back a year or two and there's Buffy, Battlestar Galactica, and, rising from the distant horizon, Twin Peaks. And let's not forget 24, which allowed you to live somebody else's much more exciting life IN REAL TIME.

Some time long ago, there existed the last human being to have read everything that had ever been written (Erasmus, Coleridge and Kant are sometimes named, without much plausibility, as candidates). Have we already passed the point of there being more hours of HBO box sets available than a single human being could watch in a lifetime, given 20-odd hours of TV a day?

That the turning point is upon us is more or less the message of tonight's much-heralded launch of Sky Atlantic, an entire satellite channel stuffed with covetable new shows like Boardwalk Empire, Treme and Mildred Pierce, along with the fifth series of Mad Men. Sure, it indicates that in the UK this stuff is enough of a draw to launch a whole channel. But more importantly, because this is what actually makes it possible, it indicates that the golden apples of this golden age are now plentiful enough to pad out a whole schedule with plausible-looking repeats (HBO's back catalogue will make up 40% of the programming). This is box-set TV.

So does this mean, as Patton Oswalt seems to suggest, that it's all over for simultaneity? Not necessarily. The weird thing is, just as Etewaf looms, there's a backlash: talent shows with timed voting schedules, rolling news and 24-hour junglecams anchor many of the newest formats fiercely in the here and now. And even as some technology makes telly less communal, others makes it more so: people have taken to live-blogging or chattering on Twitter (though this is disconcerting ? if you use the pause button to read or tweet, Twitter stays in real time while the telly slips out of phase like the handrail on an old escalator) while they watch.

This seems to hint at some stubborn cultural need to experience pop-culture simultaneously ? which is as much as to say, communally. So we have the technology for personal hand-warmers, but we still crave the campfire. We must be out of our boxes.