The noughties simultaneously saw a flowering of the best TV drama ever, some of the cheapest reality TV schlock ever, and plenty of what in more innocent times would have been referred to simply as "sick filth". More people were watching and more television was being made but simultaneously a younger generation was being lured away by the diverse and bitty pleasures of the internet. So what were the noughties all about then, televisually speaking?

Well it was sort of about box sets. In many ways DVD box sets and spiralling, multi-layered drama series are to the noughties what couples' counselling was to the '90s. The couple that watches a DVD box set together, stays together. How many teetering marriages were saved by the fact the couple were in the middle of season one of Mad Men? (I'd say 43.2%.)

The flowering of complex American drama meant that once word-of-mouth had spread about a particular series (like The Sopranos or The Wire or Battlestar Galactica or Lost) you couldn't just start watching that week and feel like you were up to speed. No, people had to get the box sets in order to catch up. If you did that you'd know that the guy glowering in the corner of scene three in episode seven was the son of the grocer Tony's cousin killed in episode four, and that Tony's wearing the same shirt he wore when he killed Big Pussy in series one. Yes, American drama series have made nerds of us all.

In the previous decade television had discovered proper continuity and series-long story arcs (most notably in Buffy the Vampire Slayer, which premiered in 1997). Prior to this, script-writers would generally hit reset at the beginning of new episodes as if nothing had happened before, and missing a week didn't matter. (In The A-Team, for example, Murdock's mental health never deteriorated despite all the gunfire or the fact his friends kept breaking him out of mental hospitals.) With the likes of The Sopranos (which actually began in 1999) or The Wire or Mad Men, characters changed and developed from week to week, and missing an instalment was like skipping a chapter in a novel or an act in a play. People even referred to these programmes as Dickensian (The Wire) or Shakespearian (The Sopranos, Battlestar Galactica) or F Scott Fitzgeraldian (Mad Men). Such talk made us feel less guilty about watching X Factor and made some feel like they weren't watching television at all. ("We don't watch television but we do watch box sets of American drama series," said Lord Snootington, adjusting his monocle and gazing out at his fantastic country estate.)

This attitude was fostered by one name in particular – US cable station HBO. While mainstream American networks had long argued that a complex back-story alienated new viewers and that controversial subjects alienated advertisers, subscription-based cable stations like HBO (or the Sci Fi Channel or AMC) simply didn't care. Once they had the viewer's subscription fees they could let their creators do whatever the hell they wanted. And they did. So the viewers readily succumbed to the unfolding narratives spewing from all powerful creators like Aaron Sorkin (The West Wing), David Simon (The Wire) and Joss Whedon (Angel, Firefly and Dollhouse) and drama was now the domain of powerful auteurs who strode above us like royalty.

Elsewhere democracy was on the move.
Cynical executives began talking about liberating the viewers from the tyranny of professionals. "Let's allow loads of ordinary people on television," said these revolutionaries. "And then let all the ordinary people at home vote on who gets to stay in a mean-spirited manner. And if people say we're cruel we'll just say it's what the people want and that the critics are elitist!"

So reality television was born. And it had a lot going for it. It was cheap – the "stars" would work for free and nobody minded the shaky cameras and dodgy sound. Sometimes it was even good (Celebrity Bainisteor, Project Runway). Indeed, when Big Brother launched in 2000 we all pretended that it was a fascinating social experiment and when Nasty Nick "broke the rules" we were horrified. Soon, however, the average contestants were psychotic fame-hungry glamour girls, oversexed racists and sociopathic loudmouths and we realised we were less academically interested in how ordinary humans interacted in a confined space (the point of the original experiment) and more pruriently obsessed with whether the freaks would have sex with one another. Even that proved to be too boring and in self-disgust we stopped watching. (Endemol announced that it would be ending the franchise in 2010.)

But Big Brother still had a lot to answer for. Our screens were awash with people exposing their lives to public scrutiny in weird programmes like How Clean is Your House, Supernanny, Wife Swap, How to Look Good Naked, and The Apprentice. Why did they do it? Attention, I suppose. Reality television blurred the distinction between wannabe celebrities and the actual celebrities who appeared on the likes of I'm a Celebrity Get Me Out of Here, Celebrity Love Island and Failte Towers. Non-entities made famous by reality television would turn up the following year on the celebrity versions of the same programmes. Nobody was even sure what fame was any more and, to make matters worse, as reality contestants mugged and gurned and hammed it up for the cameras, it was harder and harder to tell what was real. (Is the glamour girl crying or is her botox just seeping? Are that couple in love or are they just fulfilling the terms of a contract with Heat magazine?)

To confuse matters further, some decent telly makers were producing faux documentaries; The Office and Marion and Geoff and Summer Heights High muddied the waters of reality with hand-held footage and straight-to-camera confessionals. There were even programmes like The Hills – "scripted" reality shows in which "real" dead-eyed LA rich kids sheepishly followed narrative arcs written by badly paid production-runners.

By 2009 people were so confused about the nature of reality that some were actually upset by Jedward and the implication that The X Factor wasn't rewarding real talent. The most successful in a long line of "interactive" talent shows (Pop Idol, Popstars the Rivals, Britain's Got Talent) it seemed that The X Factor was only as real as WWE wrestling.

Nobody told all the young people dancing, gurning and pontificating on YouTube. And thanks to the internet you no longer needed to be Alan Yentob to broadcast badly shot footage of your latest dance moves, cats having sex, or fat blokes falling over; you just needed a video camera and an internet connection. Even telly moguls could see the importance of this newfangled internet thing. The Britain's Got Talent people made use of YouTube to disseminate Susan Boyle's "surprise" performance, thus garnering more viewers for their show. Serious television presenters continually referred to web chats and Twitter (looking like middle-aged relatives dancing to hip hop in the process). Terrestrial broadcasters had already started allowing viewers to catch up with programmes on their websites whenever it suited them. Many punters were already cutting out the middlemen by illegally downloading big shows directly after they aired in the USA.

When it came to home-produced content, however, it looked like the death of primetime (much heralded at the start of the decade) had been greatly exaggerated. It seemed that people still wanted the feeling that they were watching the same thing at the same time as their neighbours (you can't have a reality television lynch mob unless the mob gather at the correct time) and the programmers fostered this by conjuring up "big events" (opening night on Big Brother, week-long nightly drama series, Doctor Who Christmas Specials, anything with Ant and Dec, vote nights). New technology even facilitated this communal viewing experience. (Recent broadcasts of The Apprentice, for example, were spiced up by Breffny Morgan-obsessed Twitterers launching odes to their hero into cyberspace.)

And this brings us onto another big change – nobody's ashamed of their telly viewing anymore. Thanks to the erosion of boundaries between high culture and low culture on late-night arts shows ("Aqua's 'Barbie Girl' is as important as Vivaldi – discuss") watching Wife Swap or I'm a Celebrity Get Me Out of Here is now seen as being no different from going to the opera or bankrolling a Romantic poet... and if you say otherwise someone with designer glasses and a media studies degree will beat you to death with Postmodernism: A Reader.

Whilst justifiable when talking about great drama, and (relatively) harmless when expressing a love of Jedward, this culturally-endorsed lack of shame can reach into some dark places. Like when we found ourselves watching shows like The Swan (in which insecure and damaged ladies underwent serious plastic surgery so their husbands wouldn't leave them) under-class-baiting theatres of cruelty like The Jeremy Kyle Show, or shadenfreude-inducing shock documentaries with titles like The World's Fattest Midget. The normalisation of such amoral schlock was bizarre given the tabloid outrage that attended satirical shows like South Park and Brasseye (its 'Paedo-geddon' special ran in 2001) which are at least shocking for a reason.

Well, it's all part of the media landscape now. Between the box sets and the reality television and the shock documentaries and the never-ending Late Late Show and the time spent huddled around the Twitter-water-cooler solitarily watching sitcoms on a laptop, we have spent many, many hours over the past decade watching television. And why not?

Isn't watching television as respectable as Kabuki theatre, child-rearing and jazz these days?