The term Web 2.0 was dreamed up to describe community-driven phenomena such as blogs and wikis and the enormously priced businesses they inspired.
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But not everyone is buying into the label.
Participants at a recent Web 2.0 conference organised by Nomades Advanced Technologies Interactive Workshops (NATIW) in Geneva, Switzerland were scratching their heads as to what it all means.
Among them were some pretty wily web veterans, including a member of the team from Europe's Nuclear Research Centre (Cern) that actually invented the web.
Web 2.0 may not be the different species some claim, but sort of what they had in mind from the start.
"The original slogan was always to have a web that was easy to write as it was to read," said Robert Cailliau of the World Wide Web Consortium.
"We went through a sort of dark ages where the ideas survived, but the technology needed to catch up, so where we are now is indeed the point at which the people take control of the web, make their input, which is what we originally wanted.
"Our idea was for a web that was as easy to write as to read."
In the early days the web was a static medium. Early web shops were like a shop front or foyer leading to vast operations out back. In contrast, web 2.0 is about fluidity and change; the web itself is the business.
It venerates the amateur over the expert and tells us we can all collaborate in producing something worthwhile, even the truth
"The reason why so many web Web 1.0 start ups went bust is that there was so much capital cost involved in creating a web business because there was still the pretence that everything had to be created in-house," said Jeffrey Huang, director of the Media and Design Laboratory at the Swiss Federal Institute of Technology, Lausanne.
"The big change for me in Web 2.0 is that you leverage the people's resources."
This is why websites are so keen to harness what they call the wisdom of crowds.
Businesses are much cheaper to run if you get your customers to do most of the work generating content.
The best of Web 2.0 attract enough traffic to add value to the site and make it worthwhile visiting. In short, the value to users increases with the number of users.
Perhaps that is why users are made to feel so good about Web 2.0. It venerates the amateur over the expert and tells us we can all collaborate in producing something worthwhile.
But what was most fascinating about the Geneva conference was that these ideas might actually have far greater impact outside the internet, in the real world.
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Architecture, for example, is normally imposed on us from above and carved out in unforgiving stone. But, taking a cue from the web, some designers are putting the people in charge of changing the look of buildings.
Germany's Chaos Computer Club placed lights into the windows of buildings and on hoardings in Berlin and Paris so anyone could SMS the organisers and scrape the skies with their designs.
Boston's Swisshouse was designed by Jeffrey Huang for the Swiss Government and is variously described as a "prototype networked consulate" and an "inhabitable interface". It includes digital walls and interactive wallpapers to allow users to customise their surroundings.
It is architecture that anticipates what some call the internet of things where the very walls of your office could eventually interface with the internet.
And a building by Carlo Ratti Associates at the Massachusetts Institute of Technology is going to premier next year at the International Exposition in Zaragoza, Spain. Its pixelated raining walls can be programmed to do what you like.
Maybe this internet of things then will become the real departure from the original vision of the web's founders.