Forlorn and covered in dust, this was part of television history. It was the set used for early experiments in HDTV, which Kingswood began nearly thirty years ago. Graham Thomas, who showed me around, explained it took six men with two poles to lift. Which presumably explains why it's still sat there, silently watching its flat screen progeny.

High definition, as the name implies, allows you to see images in greater detail than standard definition sets. Thanks to those experiments we can now watch Barcelona play Madrid off the pitch, sink into the sofa to watch the latest Blu-Ray release or play immersive video games, all in up to five times more detail.

The first HD sets which came to market and which are often labelled 'HD Ready' or 'HD Ready720' have twice as many pixels (720 lines of 1080 pixels) as standard definition sets. Most larger screens sold today are branded 'Full HD' or 'HD Ready1080' and have five times the number (1080 lines of 1920 pixels).

You're likely to pick up a HD Ready720 set for less money and they’re worth considering if you only want a smaller screen size, where the advantage of having more pixels may be lost.

If you're buying a larger set and want to enjoy movies at their most impressive, then investing in Full HD means more pixels - and smaller pixels, at that - delivering better image quality.

Where you see 1080p or 1080i, the letters refers to the way the image is built on the screen, whether it's an 'interlaced' or 'progressive' system.

When images change on screen, the whole picture doesn't change instantaneously. In interlaced systems, odd numbered lines change first, then even numbers, so it takes two scans to change the picture. It happens in a millisecond, faster than can normally be detected by the human eye. With 'progressive' systems the picture change is achieved in one scan which sweeps from top to bottom.

Interlaced scan is usally better for watching sport, as it can display quick movements more easily. But for something slightly more sedate, such as a drama, progressive scan will deliver a clearer picture.

But don't just rely on the numbers. A 720 line set with excellent picture processing could out-perform a 1080 line TV with poor picture processing. So when buying a set check the screen quality. One tip is to ask retailers to play a movie by carrying the same player to different sets. You might not be the most popular person on a busy Saturday morning but it will give you a chance compare like with like.

To see those pictures you'll need more than a HD television, you'll also need some kind of HD video source. Unless the set has a built in HD tuner, you'll need to buy additional equipment or subscribe to a service provider.

The basic choice is between a subscription or non-subscription route. You can buy Freesat or FreeView HD kit outright or take out a subscription package with Sky or Virgin Media. Obviously, there are different costs and it all depends on what you want to watch.

Although not all TV programmes are available in HD, there's plenty of content to enjoy, like a wide choice of Blu-ray movies and video games.

The BBC have two HD channels: The BBC HD channel, which showcases the best HD programmes from across all BBC channels, from Wimbledon to Wonders of the Universe and the more recent BBC One HD channel which simulcasts a network version of the BBC One schedule, showing the majority of peak time programmes in HD.

Broadcasters are still learning how exploit the full creative potential of HD. Danielle Nagler, Head of BBC HD, says one of the biggest challenges has been encouraging producers not simply to make the same programme in HD, but to use it to make even better programmes.

In drama, this means being more filmic, with more close-ups. In natural history, perhaps including spectacular detailed helicopter shots. But there's a downside - Danielle says, 'HD can break the illusion, so it's vital to remember scratches or screws on sets become visible and artificial flowers or even some wigs that work in SD may not be convincing in HD'.

Danielle adds that HD is more precise and less forgiving. and imperfect technique can impinge on the whole work. 'In many ways HD has reminded people of the craft of filming'.

It might not surprise you to learn that the advent of HD transmission meant the installation of two and a half kilometres of cable and a hundred and eighty five separate pieces of equipment in the BBC apparatus room. It's worth watching this video Danielle made when BBC One HD launched explaining just how the channel gets to air. https://nontonwae.pages.dev/bbchd/faqs.shtml#clip

Meanwhile one former Tomorrow's World producer feels vindicated. Saul Nasse remembers filming a piece about widescreen television with Kate Bellingham at the French Open in 1991, where both HD-MAC (the high definition standard) and D-MAC (the widescreen standard) were being used.

'We'd been talking about high def on TW for years,' he says, 'and even though the pictures were brilliant, we made the point in my story that viewers were all likely to see widescreen standard definition sets in their homes long before high definition, which would probably have to wait for fully digital television. We weren't always right with our predictions on Tomorrow's World, but this time we were spot on!'

In industry circles, 2010 was 'The Year of 3D' - you could hardly move at trade shows for journalists wearing outsized glasses. It was like being at a 'Joe 90' convention! But 2011 was really the year the technology really began to sell in the high street. According to Jim Bottoms at Futuresource, over 200,000 sets are now being used in the UK and 2 million across Europe.

3D technology has been around longer than you might imagine. It's been 'the next big thing' since as far back as 1844, when David Brewster showed off his 3D photographic pictures. The first audience to pay to see a 3D film donned their glasses for The Power of Love, on 27 September, 1922. Stereoscopic 3D television was hard on its heels, demonstrated for the first time in 1928, by John Logie Baird himself.

Andy Quested who ran the recent Wimbledon 3D trials for the BBC, says it's not so much difficult to do as expensive. 'You need three times the number of cameras, one for 2D and two for each 3D position.' To create the illusion of depth perception, images first need to be recorded from two perspectives to mimic human eyes. When filming subjects relatively close to the camera – tennis or football for example – this means using a special piece of equipment with two cameras mounted side by side separated by the same distance as a person's pupils. Sometimes you want to capture images in 3D that the human eye would normally see in 2D as they're so far away – clouds for instance. In this case, the two cameras are positioned hundreds of meters apart to give us the illusion of a 3D cloud.

The camera positioning is critical. 'At Wimbledon we didn't always get that right,' admits Andy. 'But when we did, the 3D looked very good. Flare and mirror reflections were an issue too'.

If you saw the finals in 3D and are interested in how much technical learning took place, check out Andy’s blog where he goes into the 'hows', 'whys' and 'oh dears' of the experience.

Alison Hunter, who tours with the BBC Blue Room explaining technology, says one of the most common misconceptions is that 3DTV sets only deliver 3D pictures - 'Many people don't realize 3D is an option on the remote'.

And that's just the start - sometimes there's even confusion over the choice of systems.

If you're about to invest in a new TV, you need to decide how you want to watch the 3D effect – with or without glasses, and then even which type of glasses!

Those two offset images coming from the two cameras – which give that fringing or doubling effect when you look at a 3D set without special glasses – need to be filtered separately to the left and right eye. This can either be done within the set by splitting the images directionally into the viewers’ eyes, or outside the set, by getting the viewer to wear glasses.

At the moment the two most common types of glasses are the lightweight 'passive' polarised lenses and the 'active' shutter lenses.

Many people find the fit and feel of passive glasses better, but prefer the picture quality of the more expensive active-shutter glasses. It's worth asking whether you'll need to dim lights, close curtains and sit at a particular distance to get the best out of the 3D experience. Also, as Andy Quested points out, the more you pay for the glasses, active or passive, the better the experience will be.

Soon, you'll also be able to opt for 'auto-stereoscopic' or no-glasses 3D. But the convenience of not wearing glasses usually has to be balanced against the need to sit in 'sweet' viewing positions, not always practical in a family sitting room, though eye-tracking technology can improve on this problem. These sets are just coming into the market, so expect a very high price tag for the luxury of 3D with no specs.

Although 3D content is growing and some, like Sky, are investing heavily - re-cabling Premiership football grounds and commissioning feature documentaries like The Bachelor King 3D narrated by David Attenborough - others are more cautious.

Producing 3D content is expensive and according to independent technology analyst Ovum, many broadcasters rate production of 3D content and channels as their lowest technology investment priority. Manufacturers are responding to this by running their own 3D channels on internet enabled sets.

3D is an immersive experience. Fine if you're watching a football match, or a must-see movie; you can sit there with your goggles on and the curtains closed. But it doesn't sit well with channel hopping or for the increasing tendency to watch TV whist doing something else on a companion device.

With the 3D button appearing on more and more remotes, the question isn't so much how many of us will have access to 3D as how often we will use it. I suspect 3D will finally have its day when we can enjoy a fantastic 3D experience without glasses from anywhere in the room. And maybe more focus should go into developing integrated cameras, which can shoot in 3D and 2D simultaneously to make production costs more sustainable.

Because we'll only be completely won over when programme makers provide more must-see content. Maybe the Olympics are just the start!

Maggie Philbin has worked in radio and television for 30 years on a wide range of science, medical and technology programmes. She is currently a regular technology reporter on BBC 1's Inside Out.

My co-presenter, Howard Stableford, pointed to a mountain of encyclopaedias, floppy discs and maps, exclaiming how the amount of data the two videodiscs held was just "unbelievable."

It was. Timed to mark the 900th anniversary of the Domesday book, it was the work not only of a brilliant team who nursed 80s technology into delivering 21st century ambitions but over a million volunteers, mostly children, who doggedly collected 9,700 sets of data, 300,000 pictures and 147,819 pages of text to chronicle ordinary life across every part of Britain.

There were two discs, the map based Community disc, which showed Britain as seen by the people who live there and the topic based National disc, covering everything from the number of abandoned cars to the National Health Service. The country was divided into 4kmx 3km "dblocks" ; each block rationed to 3 photographs and a number of short reflections on life in that area.

It was and probably remains the biggest audience participation project ever undertaken. We were genuinely excited by it on Tomorrow's World, there was a real sense of potential and we gave the story nearly nine minutes rather than the usual three or four. The National disc even contained a primitive version of non-immersive virtual reality, with nine surrogate walks including one around a Barratt show house.

I remember the elegance of the videodisc as it slid into the player, a potent symbol of the shiny world of technology which was now beginning to gather pace, and which would soon eclipse the expensive operating system, rendering it obsolete.

But the ambition behind it was groundbreaking.

We now take the ability to access, navigate and manipulate information for granted but this was such a fresh idea we invited viewers to phone up if they wanted us to find pictures of their own town or village. It's very strange to look back on that programme and hear how thrilled Richard Street from Longborough becomes, as he recognises first the map of his village, then a field with a tractor in it and finally his local post office.

The fact that so much information was provided by children leads to some idiosyncrasies. If you look on the dblock which contains York Minster, you won't find a picture of the cathedral but a woman ironing clothes.  But children record details adults would overlook. Only a child would bother to describe how in the village of Inkpen "many people wear Wellington boots, even in summer."  Once you start reading the details, you are rewarded by the occasional sly insight . In Slawston, for example "about eight attend the weekly service, although all go to the Harvest Supper"

The children entered the data onto floppy discs using BBC Micros in their classrooms and then posted them to the BBC, where Andy Finney who worked on the project remembers the technical challenges. "We weren't even sure how to put together a master videotape with thousands of single frames on it."  He credits Roger Kelly, the technical project manager and the enthusiastic Logica team, led by Jardine Barrington-Cook, who often slept in the office, as they struggled to shoehorn advanced concepts into the tiny BBC processor. Andy's website maps the scale of the technical challenge.

At around £5000, the final system was the price of a small car, so beyond the reach of most schools and libraries. 1000 were sold but that it was never easily accessible has clearly been unfinished business for the team.

Domesday Reloaded has brought the Community Disc material to the web and the reunion for the 25th anniversary will be a special celebration.  "I'm most proud that people are finally able to access the Domesday Project information and that they are fascinated by it" says Andy. "Better late than never."

For those who want to show their children what high tech meant in 1986, the Computer Museum at Bletchley Park have set up a complete Domesday system.

For the rest of us, it highlights the issue we face if open standards are not adopted for future information. What happens if the hardware as well as the software needed to access our pictures and our written history is long gone?

But when my car was broken into recently and my voice activated, live mapping device stolen, I realised this has long since become seamlessly integrated into my life.

It's odd to think back to my first computer; grey, slow and unsightly it was the only one in the house, dominating my desk and much of my bedroom floor. I only used it for work and covered it up while I got on with life. Now my laptop rarely leaves my side.

Matt Rawlinson, media producer and technology reviewer for The Open University, agrees we use laptops in a much more casual way. "Before it was a case of making a decision to switch on the computer and sitting down to use it, now I simply flip open my laptop in front of the TV. I look things up on a whim or send a quick email without having to make that tedious round-trip to the office or bedroom."

In our house we rarely simply watch TV; Twitter and Facebook are followed at the same time, giving us 24 hr water-cooler moments. While my daughter's boyfriend was abroad, they both kept Skype open but minimized on their laptops for hours.

We use technology instinctively; it fits more naturally into how we live. Listening to BBC 5Live on the night North Yorkshire experienced a minor earthquake, I was struck by a caller saying she'd turned to Facebook to find out why crockery was rattling on her shelves.

Social technologist Suw Charman-Anderson feels the device that's changed her tech habits most is the tablet computer. "It's really convenient when you're in bed or on the sofa. We used to have a pretty strong 'no tech in the bedroom' rule, but that's being slowly relaxed for the iPad which I often use as an e-book reader."

Tablets are more "put-down-able", not as intrusive as laptops. As Suw says, they're less demanding and much more social. "If you see something you want to share with people in the room, it's easier to pass round. The fact you can flip it over and the screen re-orientates makes it much more natural to show what you're looking at."

Matt Rawlinson also has a tablet in his sights, the Android based Motorola Xoom.

Far less "put-down-able" is my mobile phone. I have it on me all day, every day because, as Matt warns, "even if you choose to opt out of carrying your digital life around in your pocket, the rest of the world doesn't, and you soon find yourself more out of touch than you ever thought you would be."

Too right. Last week, forgetting my mobile was in my other bag, I set out for a meeting, only to discover it had been postponed (by text) when I arrived. With the use of mobiles for payments predicted to take off in 2011, those moments of absent-mindedness will have bigger consequences.

Thanks to Wi-Fi and decent broadband , I completely take for granted my freedom to watch any programme, at any time, on any sized device. It's the app-based, gestural interfaces that have helped many find their way round portable devices. Suw Charman-Anderson says "Simplicity doesn't mean stupidity, and there are many apps that are much easier to use than their older Mac or PC counterparts."

But my home isn't overflowing with gadgets. I'm with Matt Rawlinson in thinking convergence - using one device for everything - is the Holy Grail.

While Suw uses a "Livescribe Echo" pen to record everything she says and writes, my 85 yr old Dad confidently sets up a nest box with a webcam. Technology is slowly becoming more comfortable, and more relevant to how we really live.

Maggie Philbin has worked in radio and television for 30 years on a wide range of science, medical and technology programmes. She is currently a regular technology reporter on BBC 1's Inside Out.

I'll confess I was a bit over-keen at first, though I still think the time I caught the cat racing down the hallway with a mouse in her mouth was a triumph of photo-journalism (the mouse survived).

But it does raise serious questions. What's okay for you to share isn’t always okay for family or friends. What for you is a moment of parental pride or exasperation, your children might see as an absolute betrayal. You never know what you might inadvertently reveal. "Your skirting boards could do with a touch up" was one comment after the mouse incident.

In our digital world it's important to remember your wry remarks and cute pictures are there to be uncovered by your children's friends, their grandchildren and certainly their future employers. Digital identity expert Dave Birch draws a firm line round family life. "Our pictures of the kids, friends, vacations and the house all go on to our friends-and-family blog, which is password-protected and always has been."

When it comes to privacy, everyone has different boundaries. They're not easy to second guess and I think it's important to ask. So you might see stunning views from a walk or Wembley stadium on my Twitter stream but you won’t see who I'm with or necessarily know why I'm there.

'Documentally', a popular blogger and social media consultant, says that when he first started using social forums his profile picture was a mash-up of his face with Che Guevara because he felt his anonymity was too valuable to sacrifice. "I didn't want a face and I didn't want a name. But now I feel differently", he says. "It's only when people can see you, have a real sense of who you are, that new connections can be made. I have to be myself, not a shadowy figure. Opening up is the only way to share."

One of the hardest decisions I made recently was whether to tell my Twitter followers about my mother's death. Grief is intensely private, yet I felt odd stepping round it. After a few weeks, I wrote a very brief blog and my family was immensely touched by the warmth of the response.

Internet technologist Benjamin Ellis says he's also had some really positive benefits from revealing more about himself online, from better birthday presents to meeting new and interesting people who would never have otherwise found him. But recently he had a reminder that there were people out there who knew much more about him than he did about them or indeed about himself. "Because of my online writing, an older half-sister I have never met, who lives on the other side of the world, was able to find my father and myself when she decided to track us down".

For the most part, our social networks are benign. There are issues about bullying and it obviously makes sense not to geo-tag your home or let cyber-space know you're on holiday for a month.

What we can't predict is how, as technology moves on, people may be able to aggregate and analyse our data in ways we can't even imagine. As Benjamin Ellis says, "Modern face recognition software, combined with our online photo libraries and mobile phones that now track the location of where pictures are taken, may mean much, much more of our life becomes "discoverable" in the future." He has also set some basic rules for himself: "I never post anything if I am tired, emotional, or under the influence of too much coffee or wine!"

In a nutshell, be cautious. Don't imagine you can be protected by operating under a pseudonym, because search engines make it much easier to put two and two together. And if you share something personal or private with someone who's active in the online world, Benjamin suggests you "make it clear it’s NSFTB! (not suitable for the blog)", a term coined by marketeer Seth Godin.

But there are advantages. Dave Birch says "I'm a bit jealous of this generation: when they are my age they'll be able to look back on school, university, gap year, work, parties and weddings by going online. Whereas, it took me a week to find half-a-dozen photos from my university days for my 30-year reunion."